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1. The Blue‐LED‐Sensitive Naphthoquinone‐Imidazolyl Derivatives as Type II Photoinitiators of Free Radical Photopolymerization

Author

Timur Borjigin, Michael Schmitt, Nicolas Giacoletto, Alexandre Rico, Hugo Bidotti, Malek Nechab, Yijun Zhang, Bernadette Graff, Fabrice Morlet‐Savary, Pu Xiao, Frédéric Dumur, and Jacques Lalevée

Subjects
3D printing, blue‐LED‐sensitivity, direct laser write, free radical photopolymerization, naphthoquinone derivatives, photoinitiator, Physics, QC1-999, Technology
Abstract

Abstract In this work, new naphthoquinone‐based photoinitiators are synthesized and applied for the first time in free radical photopolymerization. In the presence of acrylate monomers, these PIs display excellent photoinitiation capabilities under blue‐light LED@405 nm irradiation in a two‐component photoinitiating system in which the additive is a common iodonium salt (bis‐(4‐tert‐butylphenyl)iodonium hexafluorophosphate ‐ Iod) or a tertiary amine (ethyl 4‐dimethylaminobenzoate ‐ EDB). In controlled tests, the polymerization performance of dye4/Iod is equal to or better than that of common commercial Type II photoinitiators (2‐isopropylthioxanthone and benzophenone). Meanwhile, only a trace amount of photoinitiator is required (as low as 0.05%) to initiate the photopolymerization. It is worth noting that some of these compounds can also be used in one‐component photoinitiating system (monocomponent Type II behavior) and exhibit high photoinitiation ability. A series of complementary characterization analyses of two new naphthoquinone dyes (i.e. dye 1 and dye 4) with very similar chemical structures are carried out to investigate the relevant photochemical mechanism. Finally, 3D printing experiments are carried out by a simple and convenient Direct Laser Write (DLW) technique.

Published
2023
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2. On-surface homocoupling reactivity of a chiral bifunctional bromoindanone molecule on Cu(111)

Author

Fatima Hussein, Corentin Pigot, Francisco Romero Lairado, Marco Minissale, Eric Salomon, Thierry Angot, Frédéric Dumur, Malek Nechab, Didier Gigmes, Sylvain Clair, Luca Giovanelli, Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), and ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017)

Subjects
[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Materials Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, Catalysis
Abstract

International audience; On-surface synthesis has provided exciting concepts for the building of covalently bonded molecular nanostructures as well as the exploration of new synthetic pathway alternatives to chemical synthesis in solution. The surface-supported reaction of precursor molecules can result in the formation of 2D molecular networks as well as novel 0D molecular structures. In this study, we investigate in ultrahigh vacuum by low-temperature scanning tunneling microscopy the adsorption of the chiral molecule (R)-6-bromo-3-phenyl-2,3-dihydro-1H-inden-1-one (BrPhINDO) on the Cu(111) surface. Annealing an as-deposited layer of molecules allows to activate two kinds of homocoupling reactions, the Ullmann-like coupling and the Knoevenagel reaction, resulting in the formation of various low-dimensional structures. By studying their prochirality and comparing with the products obtained with the enantiomer precursor, we demonstrate adsorption-induced chiral inversion inducing partial racemization.

Published
2022
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3. Synergistic approach of type I hybrid complexes for highly efficient metal-based initiating strategies: Toward low energy-consuming polymerization for thermoplastic composite implementation

Author

Marie Le Dot, Nicolas Giacoletto, Fabrice Morlet-Savary, Bernadette Graff, Valérie Monnier, Didier Gigmes, Malek Nechab, Frédéric Dumur, Pierre Gerard, Jacques Lalevée, Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Spectropôle - Aix Marseille Université (AMU SPEC), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Arkema (Arkema), and ANR-19-CE07-0042,NoPerox,Des systèmes sans Peroxide pour la synthèse de (photo)polymères(2019)

Subjects
Polymers and Plastics, Organic Chemistry, Materials Chemistry, General Physics and Astronomy, [CHIM]Chemical Sciences
Abstract

International audience; From a circular plastic economy perspective, a new configuration of Metal Acetylacetonate Bidentate Ligand Interaction (MABLI) mechanism adapted to the chemistry of the recyclable Elium® thermoplastic resins has been recently discovered to initiate the free radical polymerization of these resins under mild conditions (under air, at room temperature, non-purified monomers, absence of hazardous chemical substances). This initiating strategy is based on the synergy between the initial MABLI couple and a phosphine oxide (Type I photoinitiator). Despite the absence of irradiation, the mere presence of the phosphine oxide reduced significantly the curing time and the final conversion obtained is nearly 100%. In order to dismantle the role of each component and to predict new highperformance MABLI redox initiating systems based on a similar configuration, a mechanistic study was pursued. It has resulted in the identification of new hybrid complexes obtained by ligand exchange between the photoinitiator and the metallic complex. On the other hand, presence of the Type I photoinitiator can level up the initiating strategy by combining MABLI and photoactivation into a dual cure approach: thereby, the photolysis yield and the polymerization efficiency of the complexed form of the phosphine oxide was studied and compared to the free form of the photoinitiator.

Published
2023
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4. 5,12‐Dialkyl‐5,12‐dihydroindolo[3,2‐ a ]carbazole‐Based Oxime‐Esters for LED Photoinitiating Systems and Application on 3D Printing

Author

Fatima Hammoud, Nicolas Giacoletto, Malek Nechab, Bernadette Graff, Akram Hijazi, Frédéric Dumur, Jacques Lalevée, Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Libanaise, and ANR-19-CE07-0042,NoPerox,Des systèmes sans Peroxide pour la synthèse de (photo)polymères(2019)

Subjects
Oxime-esters, dual initiators, dialkyl, Polymers and Plastics, General Chemical Engineering, carbazole, Organic Chemistry, Materials Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, photoinitiators, dihydroindolo, visible light
Abstract

International audience; In order to expand the application of oxime-esters (OXEs) and to introduce a one-component photoinitiating system of high performance in visible light photopolymerization, we designed and synthetized a series of 5,12-dihexyl-5,12-dihydroindolo[3,2-a]carbazole-based oximeesters with visible absorption abilities. Notably, when irradiated with light-emitting diodes at 405 nm, the proposed structures could undergo a direct cleavage of the NO bond followed by decarboxylation, generating free radicals capable to efficiently initiate free radical photopolymerizations (FRP). Furthermore, the new OXEs showed good thermal initiation abilities and could be used as dual photo and thermal initiators. An interesting structure/reactivity/efficiency relationship could be obtained by comparing the reactivity of the different radicals generated upon photoexcitation at identical chromophore but also by comparing the photoinitiating ability of our series of dyes with that of another series of dyes designed to exhibit a lower solubility in resins. Indeed, solubility of dyes can constitute a major issue adversely affecting the photoinitiating ability. Chemical mechanisms were studied through different techniques including real-time Fourier Transform Infrared Spectroscopy (RT-FTIR), UV-visible absorption spectroscopy, fluorescence (time-resolved or steady state) as well as molecular modelling calculations. Eventually, the usage of the investigated OXEs in new photosensitive 3D printing resins is also presented.

Published
2022
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5. Interpenetrating polymer network hydrogels using natural based dyes initiating systems: Antibacterial activity and 3D/4D performance

Author

Hong Chen, Christophe Regeard, Hanène Salmi, Fabrice Morlet-Savary, Nicolas Giacoletto, Malek Nechab, Pu Xiao, Frédéric Dumur, Jacques Lalevée, Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Australian National University (ANU), Dumur, Frederic, and ANR-19-CE07-0042,NoPerox,Des systèmes sans Peroxide pour la synthèse de (photo)polymères(2019)

Subjects
interpenetrating polymer network, silver nanoparticles, [CHIM.MATE] Chemical Sciences/Material chemistry, reversible shape-memory effect, Polymers and Plastics, Organic Chemistry, Materials Chemistry, General Physics and Astronomy, [CHIM.MATE]Chemical Sciences/Material chemistry, 3D/4D printing, antibacterial materials
Abstract

International audience; In the past few decades, interpenetrating polymer network (IPN) hydrogels have attracted huge attentions due to their special cell-like structures, interpenetrating interface, and two-phase continuity, which has special synergistic effects on performance or function. In this work, eleven different dyes based on 1-aryl-3-(2,4,5trimethoxyphenyl)prop-2-en-1-one or 3-aryl-1-(3,4,5-trimethoxyphenyl)prop-2-en-1one were firstly synthesized, and combined with an amine (i.e. ethyl l,4-(dimethylamino)benzoate, EDB) and an iodonium salt (bis(4-tert-butylphenyl) iodonium hexafluorophosphate, Iod) (PISs) as the three-component photoinitiating systems (PIS) to induce both the free radical photopolymerization (FRP) of polyethylene glycol diacrylate (PEG-DA) and the cationic photopolymerization (CP) of 3,4-epoxycyclohexylmethyl-3',4'-epoxy-cyclohexane carboxylate (EPOX) under the irradiation of LED@405nm. The best candidates were selected from the proposed eleven different dyes to study the involved oxidation-reduction reaction mechanisms 2 through several characterization techniques. The best candidates were also used to prepare PEG-DA/EPOX interpenetrated polymer networks (IPNs). More interestingly, the stable 3D patterns have been successfully produced through direct laser write (DLW) technology, meanwhile, the silver cations could also be reduced in situ into silver nanoparticles. Furthermore, 4D printing could be achieved since all the obtained 3D patterns exhibited reversible swelling properties and shape-memory effect caused by swelling and dehydration processes. Parallel to this, influence of AgNPs on the mechanical properties of the 3D-printed objects and on IPNs has also been systematically studied. Finally, the obtained IPN polymers containing silver nanoparticles (AgNPs) exhibited antibacterial activities for Gram-positive bacteria (e.g. Staphylococcus aureus) and Gram-negative bacteria (e.g. Pseudomonas aeruginosa).

Published
2022
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6. Enantioselective Radical Reactions Using Chiral Catalysts

Author

Shovan Mondal, Frédéric Dumur, Didier Gigmes, Mukund P. Sibi, Michèle P. Bertrand, Malek Nechab, Syamsundar College, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and North Dakota State University (NDSU)

Subjects
Stereoisomerism, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, Oxidation-Reduction, Catalysis, ComputingMilieux_MISCELLANEOUS, Hydrogen, Lewis Acids
Abstract

Benefiting from the impressive increase in fundamental knowledge, the last 20 years have shown a continuous burst of new ideas and consequently a plethora of new catalytic methods for enantioselective radical reactions. This review aims to provide a complete survey of progress achieved over this latter period. The first part of this review focuses on the use of chiral organocatalysts, and these include catalysts covalently linked to the substrate and those that interact with the substrate by weaker interactions like hydrogen bonds. The second part of the review is devoted to transition-metal redox catalysis which is organized according to increasing atomic number for the first-row transition metals (Ti, Cr, Fe, Mn, Co, Ni, Cu). Bioinspired manganese- and iron-mediated hydroxylations and oxidations are also discussed. A specific section is dedicated to the reactivity of Ru, Rh, and Ir complexes as Lewis acids with a special focus on complexes chiral at metal. Absorption of photons result in different events such as energy transfer, single-electron transfer, and hydrogen-atom transfer facilitating the formation of radicals. Organocatalysis has been successfully combined with photocatalysts, a reactivity which has opened new pathways enlarging the number of radical precursors available. The merger of photocatalysis with organo- or metalla-photocatalysis has brought novelty and allowed for the discovery of a large number of original transformations. The use of enzyme-catalyzed reactions involving radical intermediates which also largely benefit from visible-light irradiation are included in the review. This review provides a comprehensive inventory of progress in enantioselective radical reactions with a goal of detailing the reaction mechanisms involved in these transformations such that any nonspecialist could find their own creativity to invent yet unknown applications.

Published
2022
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7. Sunlight Induced Polymerization Photoinitiated by Novel Push–Pull Dyes: Indane‐1,3‐Dione, 1H‐Cyclopenta[b]Naphthalene‐1,3(2H)‐Dione and 4‐Dimethoxyphenyl‐1‐Allylidene Derivatives

Author

Ke Sun, Corentin Pigot, Yijun Zhang, Timur Borjigin, Fabrice Morlet‐Savary, Bernadette Graff, Malek Nechab, Pu Xiao, Frédéric Dumur, Jacques Lalevée, Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Australian National University - Department of engineering (ANU), Australian National University (ANU), Dumur, Frederic, and ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017)

Subjects
[CHIM.MATE] Chemical Sciences/Material chemistry, Polymers and Plastics, Organic Chemistry, Materials Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, Physical and Theoretical Chemistry, Condensed Matter Physics
Abstract

International audience; The free radical polymerization of acrylates photo-initiated by push–pull dye-based photoinitiating systems (PISs) is widely investigated in previous works. As a supplementary investigation on push–pull dyes, here in this article, 25 push–pull structures comprising electron acceptors derived from indane-1,3-dione and 1H-cyclopenta[b]naphthalene-1,3(2H)-dione (series 1) and 4-dimethoxyphenyl-1-allylidene moieties (series 2) and various electron donors are synthesized and examined as innovative structures for photoinitiation. Among the two series of dyes examined in this work and by monitoring the polymerization processes by RT-FTIR measurements, four dyes are determined as exhibiting excellent photoinitiation performances and these dyes are selected to perform further studies concerning the chemical mechanisms occurring inside the three-component PISs, for example, steady state photolysis, fluorescence quenching measurements, and cyclic voltammetry. Markedly, their reactivity is also proved by photoinitiation performance upon sunlight. These results prompt us to develop high performance push–pull dyes as photosensitizers and sunlight can be used as a mild and ecofriendly light source, which can advantageously replace LEDs for the free radical photopolymerization in the future. Finally, the formation of 3D patterns with an excellent gradient of resolution is successfully achieved by the direct laser write (DLW) with/without silica fillers.

Published
2022
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8. Effect of Decarboxylation on the Photoinitiation Behavior of Nitrocarbazole-Based Oxime Esters

Author

Shaohui Liu, Nicolas Giacoletto, Michael Schmitt, Malek Nechab, Bernadette Graff, Fabrice Morlet-Savary, Pu Xiao, Frédéric Dumur, Jacques Lalevée, Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Australian National University (ANU), ANR-19-CE07-0042,NoPerox,Des systèmes sans Peroxide pour la synthèse de (photo)polymères(2019), and Dumur, Frederic

Subjects
Inorganic Chemistry, [CHIM.POLY] Chemical Sciences/Polymers, [CHIM.POLY]Chemical Sciences/Polymers, Polymers and Plastics, Organic Chemistry, Materials Chemistry
Abstract

International audience; A series of 50 oxime esters bearing various substituents were designed and synthesized as photoinitiators (48 of them were never synthesized before and only B1 and B10 were reported). Good light absorption properties in the visible range were observed for these oxime esters. Some structures exhibited better photoinitiation abilities than diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) upon exposure to a LED@405 nm. Interestingly, PIs with methyl substituent on the oxime ester group have better photoinitiation performance than the others. Substituent effects were investigated through molecular orbitals calculations, the detection of CO2, and the investigation of the generated free radicals. The results demonstrate that the substituents on the oxime ester group exert major effects on the photoinitiation ability via the decarboxylation reaction. In addition, a chemical mechanism was proposed. 3D printed objects were successfully obtained by using the most reactive oxime ester as photoinitiator, and their thermal initiation behaviors of several oxime esters were also studied (dual thermal/photochemical initiator behavior).

Published
2022
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9. Substituent Effects on Photoinitiation Ability of Coumarin-Based Oxime-Ester Photoinitiators for Free Radical Photopolymerization

Author

Nicolas Giacoletto, Didier Gigmes, Guillaume Noirbent, Frédéric Dumur, Bernadette Graff, Fatima Hammoud, Akram Hijazi, Malek Nechab, Jacques Lalevée, Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ecole Doctorale des Sciences et de la Technologie (EDST), Lebanese University [Beirut] (LU), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), and Dumur, Frederic

Subjects
dual initiators, Absorption spectroscopy, Radical, Radical polymerization, Substituent, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, chemistry.chemical_compound, Materials Chemistry, General Materials Science, Reactivity (chemistry), photoinitiators, visible light, [CHIM.MATE] Chemical Sciences/Material chemistry, coumarins, Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, Chromophore, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Oxime-esters, Photopolymer, Polymerization, 0210 nano-technology
Abstract

International audience; In this paper, a series of coumarin chromophore-based oxime-esters was designed and synthesized as visible light photoinitiators (PIs). Interestingly, upon exposure to irradiation of a LED at 405 nm, the investigated oxime-esters (OXEs) could undergo a direct photocleavage, followed by decarboxylation, generating active free radicals capable to effectively initiate acrylate polymerization. Seven of the 10 investigated OXEs have never been synthesized in the literature. Markedly, the new proposed structures exhibit also thermal initiation ability and can be used as dual photo and thermal initiators. In addition, the oxime-ester system was also paired with an iodonium salt and exhibited a higher efficiency in free radical polymerization (FRP). The chemical mechanisms and the structure/reactivity/efficiency relationships were investigated through different techniques including real-time Fourier Transform Infrared Spectroscopy (RT-FTIR), UV-visible absorption spectroscopy, fluorescence (time-resolved or steady state), cyclic voltammetry as well as molecular modelling calculations. As a proof of their remarkable polymerization performance, the new OXEs were also used at 405 nm for direct laser write applications.

Published
2021
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10. Synthesis, optical and electrochemical properties of a series of push-pull dyes based on the 4,4-bis(4-methoxy phenyl)butadienyl donor

Author

Frédéric Dumur, Guillaume Noirbent, Corentin Pigot, Didier Gigmes, Thanh-Tuân Bui, Sébastien Péralta, Malek Nechab, Sylvain Duval, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physico-chimie des Polymères et des Interfaces (LPPI), Fédération INSTITUT DES MATÉRIAUX DE CERGY-PONTOISE (I-MAT), CY Cergy Paris Université (CY)-CY Cergy Paris Université (CY), Ecole Nationale Supérieure de Chimie de Lille (ENSCL), Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017), ANR-17-CE08-0054,VISICAT,Nouveaux Photocatalyseurs Redox pour la Synthèse sous Lumière Visible de Réseaux Polymères Interpénétrés(2017), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), and Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille

Subjects
chemistry.chemical_classification, Absorption spectroscopy, 010405 organic chemistry, Chemistry, Process Chemistry and Technology, General Chemical Engineering, Solvatochromism, solvatochromism, indanedione, TNF, TCF, [CHIM.MATE]Chemical Sciences/Material chemistry, Electron acceptor, 010402 general chemistry, Photochemistry, Electrochemistry, 01 natural sciences, Push-pull dyes, Michler's aldehyde, 0104 chemical sciences, Solvent, Polarizability, rhodanine, Absorption (chemistry), Cyclic voltammetry
Abstract

International audience; A series of twelve dyes based on the 4,4-bis(4-methoxyphenyl)butadienyl donor and differing by the electron acceptors have been designed and synthesized. The different dyes were characterized by UV-visible absorption spectroscopy as well as cyclic voltammetry. By fine tuning the electron-accepting ability of the fourteen selected acceptors, dyes absorbing between 400 and 650 nm could be obtained with this π-extended donor. To get a deeper insight into the optical properties, solvatochromism was investigated in 23 different solvents and remarkable linear correlations could be obtained using the Taft and Catalan solvatochromism scales. A comparison with four dyes used as reference compounds and differing from the series of twelve dyes by the structure of the electron-donating groups was also established so that the electron releasing ability of the 4,4-bis(4-methoxyphenyl)butadienyl donor could be compared with the reference ones. To prepare these four references compounds, only two electron acceptors previously used for the design of the twelve dyes have been employed. Interestingly, variation of the absorption maxima of the twelve dyes was determined as being more influenced by the polarizability of the solvent rather than by its polarity. To support the experimental results, theoretical calculations were carried out.

Published
2021
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11. Synthesis, optical and electrochemical properties of a series of push-pull dyes based on the 2-(3-cyano-4,5,5- trimethylfuran-2(5H)-ylidene)malononitrile (TCF) acceptor

Author

Didier Gigmes, Thanh-Tuân Bui, Malek Nechab, Frédéric Dumur, Sébastien Péralta, Corentin Pigot, Guillaume Noirbent, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physico-chimie des Polymères et des Interfaces (LPPI), Fédération INSTITUT DES MATÉRIAUX DE CERGY-PONTOISE (I-MAT), CY Cergy Paris Université (CY)-CY Cergy Paris Université (CY), ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017), ANR-17-CE08-0054,VISICAT,Nouveaux Photocatalyseurs Redox pour la Synthèse sous Lumière Visible de Réseaux Polymères Interpénétrés(2017), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)

Subjects
Materials science, Polarity (physics), General Chemical Engineering, solvatochromism, Electron donor, 02 engineering and technology, 010402 general chemistry, Electrochemistry, Photochemistry, 01 natural sciences, chemistry.chemical_compound, Claisen-Schmidt condensation, Malononitrile, chemistry.chemical_classification, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Process Chemistry and Technology, Solvatochromism, near infrared absorption, visible absorption, TCF, Chromophore, Electron acceptor, 021001 nanoscience & nanotechnology, Acceptor, Push-pull dyes, 0104 chemical sciences, chemistry, 0210 nano-technology
Abstract

International audience; A series of chromophores was designed and synthesized using 2-(3-cyano-4,5,5-trimethylfuran-2 (5H)-ylidene) malononitrile (TCF) as the electron acceptor and differing from each other by the use of thirteen different electron donors. The different dyes were characterized for their optical and electrochemical properties and theoretical calculations were also carried out to support the experimental results. By changing the electron donor in the thirteen dyes, chromophores absorbing between 430 nm and 700 nm could be synthesized. Solvatochromism of the different dyes was analyzed in 23 solvents of different polarity and a positive solvatochromism was determined for all chromophores using the semi-empirical solvent polarity scales based on the Kamlet-Taft parameters (π *) or the Catalan parameters (SdP and SPP).

Published
2021
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12. N-ethyl Carbazole-1-Allylidene-Based Push-Pull Dyes as Efficient Light Harvesting Photoinitiators for Sunlight Induced Polymerization

Author

Pu Xiao, Shaohui Liu, Corentin Pigot, Bernadette Graff, Hong Chen, Jacques Lalevée, Ke Sun, Malek Nechab, Frédéric Dumur, Fabrice Morlet-Savary, Institut de Science des Matériaux de Mulhouse (IS2M), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Australian National University (ANU), Dumur, Frederic, Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017)

Subjects
[CHIM.POLY] Chemical Sciences/Polymers, Materials science, Polymers and Plastics, Tertiary amine, Radical polymerization, General Physics and Astronomy, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, chemistry.chemical_compound, Materials Chemistry, push-pull dye, Acrylate, free radical polymerization, Organic Chemistry, Photodissociation, LED, three-component system, 3D printing, Chromophore, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Photopolymer, [CHIM.POLY]Chemical Sciences/Polymers, Polymerization, chemistry, sunlight, Cyclic voltammetry, 0210 nano-technology
Abstract

International audience; In this article, the free radical polymerization of acrylates was successfully achieved with a series of twelve push-pull chromophores comprising the N-ethyl carbazole-1-allylidene group as the electron-donating group. Using this strong donor, the resulting dyes, never synthesized before, could efficiently initiate the free radical photopolymerization of acrylates upon mild irradiation conditions e.g. using sunlight. These novel multi-component systems comprising the above mentioned push-pull dyes, a tertiary amine (ethyl dimethylaminobenzoate EDB) and an iodonium salt could act as efficient photoinitiating systems (PISs) in free radical polymerization (FRP), leading to the formation of 3D patterns with precise shapes under the direct laser write (DLW) approach. Among these new PISs, dyes 3, 6, 7 and 8 were selected due to their efficient photoinitiation performances for chemical mechanism studies including steady state photolysis, fluorescence quenching measurements, electron spin resonance (ESR) spin-trapping experiments and cyclic voltammetry. Markedly, their excellent photochemical reactivities prompted us to investigate the performance of these multi-component photoinitiating systems upon sunlight as an ecofriendly approach. As a result, this research proved that sunlight could be used as a potential light source that can advantageously replace LEDs when highly reactive push-pull dyes are used as photosensitizers for the free radical photopolymerization of acrylate resins. Finally, 3D patterns could be prepared with the new photocomposites, and silica fillers could be even incorporated within the photosensitive resins so that a gradient of resolution could be successfully demonstrated.

Published
2021
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13. Dyes with tunable absorption properties from the visible to the near infrared range : 2,4,5,7-tetranitrofluorene (TNF) as a unique electron acceptor

Author

Malek Nechab, Corentin Pigot, Frédéric Dumur, Guillaume Noirbent, Sébastien Péralta, Didier Gigmes, Thanh-Tuân Bui, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physico-chimie des Polymères et des Interfaces (LPPI), Fédération INSTITUT DES MATÉRIAUX DE CERGY-PONTOISE (I-MAT), CY Cergy Paris Université (CY)-CY Cergy Paris Université (CY), ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017), and ANR-17-CE08-0054,VISICAT,Nouveaux Photocatalyseurs Redox pour la Synthèse sous Lumière Visible de Réseaux Polymères Interpénétrés(2017)

Subjects
Materials science, Absorption spectroscopy, General Chemical Engineering, solvatochromism, TNF, Electron donor, 02 engineering and technology, 010402 general chemistry, Photochemistry, Electrochemistry, 01 natural sciences, chemistry.chemical_compound, chromophore, mechanosynthesis, Absorption (electromagnetic radiation), chemistry.chemical_classification, Range (particle radiation), [CHIM.ORGA]Chemical Sciences/Organic chemistry, Process Chemistry and Technology, Near-infrared spectroscopy, Solvatochromism, near infrared absorption, Electron acceptor, 021001 nanoscience & nanotechnology, Push-pull dyes, 0104 chemical sciences, chemistry, Knoevenagel reaction, tetranitrofluorene, 0210 nano-technology
Abstract

International audience; Fourteen dyes based on 2,4,5,7-tetranitrofluorene (TNF) as the electron acceptor have been designed and prepared in a one-step synthesis. By modifying the electron donor, optical properties of the dyes could be efficiently tuned and an absorption ranging between 450 nm and 700 nm could be determined by UV-visible absorption spectroscopy. To get a deeper insight into the optical properties, solvatochromism of the fourteen dyes has also been examined. For all dyes, a positive solvatochromism was determined using different solvent polarity scales such as the Kamlet-Taft and the Catalan empirical scales. Finally, electrochemical properties were also examined, and a comparison of the electrochemical and optical bandgaps could be established. Theoretical calculations were also performed to characterize the different dyes.

Published
2021
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14. Push-pull dyes based on Michler's aldehyde: Design and characterization of the optical and electrochemical properties

Author

Corentin Pigot, Sébastien Péralta, Thanh-Tuân Bui, Malek Nechab, Frédéric Dumur, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physico-chimie des Polymères et des Interfaces (LPPI), Fédération INSTITUT DES MATÉRIAUX DE CERGY-PONTOISE (I-MAT), CY Cergy Paris Université (CY)-CY Cergy Paris Université (CY), and ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017)

Subjects
Process Chemistry and Technology, General Chemical Engineering, solvatochromism, rhodanine, TNF, TCF, [CHIM.MATE]Chemical Sciences/Material chemistry, Push-pull dyes, Michler's aldehyde
Abstract

International audience; Fifteen dyes based on Michler's aldehyde used as the electron donating group and differing by the electron accepting groups have been designed and synthesized. Interestingly, all dyes showed a broad absorption extending over the visible range. Examination of the solvatochromism in twenty-three solvents of different polarities revealed these dyes to give remarkable linear correlations using the Kamlet-Taft solvent polarity scale or the SPP Catalan empirical scales. The different dyes were also characterized by photoluminescence spectroscopy as well as cyclic voltammetry. To get a deeper insight into the optical properties of the different dyes, theoretical calculations were also carried out.

Published
2022
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15. Novel Push–Pull Dyes Derived from 1H-cyclopenta[b]naphthalene-1,3(2H)-dione as Versatile Photoinitiators for Photopolymerization and Their Related Applications: 3D Printing and Fabrication of Photocomposites

Author

Didier Gigmes, Pu Xiao, Malek Nechab, Corentin Pigot, Yijun Zhang, Ke Sun, Frédéric Dumur, Shaohui Liu, Jacques Lalevée, Fabrice Morlet-Savary, Bernadette Graff, Damien Brunel, Institut de Science des Matériaux de Mulhouse (IS2M), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Australian National University (ANU), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017)

Subjects
Materials science, Tertiary amine, Radical polymerization, naphthalene-1,3-dione, 02 engineering and technology, naphthalene-1, lcsh:Chemical technology, 010402 general chemistry, Photochemistry, 01 natural sciences, Catalysis, lcsh:Chemistry, chemistry.chemical_compound, 3-dione, lcsh:TP1-1185, push-pull dye, Physical and Theoretical Chemistry, chemistry.chemical_classification, free radical polymerization, LED, three-component system, [CHIM.MATE]Chemical Sciences/Material chemistry, 3D printing, Electron acceptor, Chromophore, 021001 nanoscience & nanotechnology, 3. Good health, 0104 chemical sciences, Light intensity, Monomer, Photopolymer, lcsh:QD1-999, chemistry, Polymerization, push–pull dye, 0210 nano-technology
Abstract

A series of eleven push&ndash, pull chromophores with specific structures have been designed for the free radical polymerization of acrylates, but also for the fabrication of photocomposites and 3D-printed structures. New photoinitiating systems comprising the different push&ndash, pull dyes showed excellent photochemical reactivities at 405 nm. Notably, polymerization reactions could be initiated with light-emitting diodes (LEDs) which constitute a unique opportunity to promote the free radical polymerization under mild conditions, i.e., low light intensity (e.g., sunlight) and under air. Photopolymerization is an active research field, and push&ndash, pull dyes have already been investigated for this purpose. Besides, it remains of crucial interest to investigate new reactive structures capable of efficiently initiating photopolymerization reactions. The plausible potential of these structures to act as efficient photoinitiators in vat photopolymerization (or 3D printing) and fabrication of photocomposites prompts us to select eleven new push&ndash, pull dyes to design multi-component photoinitiating systems activable with LEDs emitting at 405 nm. Precisely, a tertiary amine, i.e., ethyl dimethylaminobenzoate (EDB) used as an electron/hydrogen donor and an iodonium salt used as an electron acceptor were selected to behave as powerful co-initiators to construct three-component photoinitiating systems (PISs) with the different push&ndash, pull dyes. Among these new PISs, dye 8 and 9-based PISs could efficiently promote the free radical photopolymerization of acrylates upon exposure to a LED emitting at 405 nm also upon sunlight irradiation, highlighting their huge performance. Photoinitiating abilities could be explained on the basis of steady state photolysis experiments. Fluorescence measurements and electron spin resonance (ESR) spin-trapping experiments were also performed to obtain a deeper insight into the chemical mechanisms supporting the polymerization reaction and determine the way the initiating species, i.e., the radicals, are observed. Finally, two investigated dye-based PISs were applied to the fabrications of photocomposites. Three-dimensional patterns with excellent spatial resolutions were generated by the laser writing technique to identify the effects of photopolymerization of acrylates both in the absence and presence of fillers (silica). Interestingly, comparison between the 3D objects fabricated by the PISs/monomer systems and the PISs/monomer/filler photocomposites indicates that the newly designed photocomposites are suitable for practical applications.

Published
2020
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16. New push-pull dyes based on 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene)malononitrile: An amine-directed synthesis

Author

Sébastien Péralta, Guillaume Noirbent, Sylvain Duval, Frédéric Dumur, Pierre-Henri Aubert, Thanh-Tuan Bui, Malek Nechab, Corentin Pigot, Didier Gigmes, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physico-chimie des Polymères et des Interfaces (LPPI), Fédération INSTITUT DES MATÉRIAUX DE CERGY-PONTOISE (I-MAT), Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille, Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017), ANR-17-CE08-0054,VISICAT,Nouveaux Photocatalyseurs Redox pour la Synthèse sous Lumière Visible de Réseaux Polymères Interpénétrés(2017), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), and CY Cergy Paris Université (CY)-CY Cergy Paris Université (CY)

Subjects
chemistry.chemical_classification, Process Chemistry and Technology, General Chemical Engineering, Aromatization, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Aldehyde, Medicinal chemistry, 0104 chemical sciences, chemistry.chemical_compound, chemistry, Nucleophile, [CHIM]Chemical Sciences, Knoevenagel condensation, Amine gas treating, Piperidine, 0210 nano-technology, Derivative (chemistry), ComputingMilieux_MISCELLANEOUS, Malononitrile
Abstract

International audience; A series of twelve dyes have been designed using 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-yli-dene)malononitrile as the electron acceptor. While using piperidine as a classical base for the Knoevenagel reaction , a nucleophilic attack of the amine on the formed push-pull chromophore occurred, producing an azaflu-orenone derivative. By varying the amine, a series of azafluorenones could be obtained. By using an aldehyde of extended conjugation, a spontaneous aromatization following the cyclization reaction could also be demonstrated. The optical, electrochemical properties of the different dyes were examined. Theoretical calculations were also carried out to support the experimental results.

Published
2020
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17. Free Radical Photopolymerization and 3D Printing Using Newly Developed Dyes: Indane-1,3-Dione and 1H-Cyclopentanaphthalene-1,3-Dione Derivatives as Photoinitiators in Three-Component Systems

Author

Malek Nechab, Fabrice Morlet-Savary, Didier Gigmes, Jacques Lalevée, Frédéric Dumur, Pu Xiao, Corentin Pigot, Ke Sun, Bernadette Graff, Shaohui Liu, Hong Chen, Institut de Science des Matériaux de Mulhouse (IS2M), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Research School of Chemistry, Australian National University (ANU), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Dumur, Frederic

Subjects
[CHIM.POLY] Chemical Sciences/Polymers, Materials science, Tertiary amine, Radical, Radical polymerization, Indane, 02 engineering and technology, 010402 general chemistry, Photochemistry, lcsh:Chemical technology, 01 natural sciences, Catalysis, lcsh:Chemistry, chemistry.chemical_compound, lcsh:TP1-1185, push-pull dye, Physical and Theoretical Chemistry, chemistry.chemical_classification, free radical polymerization, LED, three-component system, 3D printing, Electron acceptor, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Light intensity, Photopolymer, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Polymerization, lcsh:QD1-999, push–pull dye, 0210 nano-technology
Abstract

The design of photoinitiating systems with excellent photochemical reactivities at 405nm LED is one of the obstacles to efficiently promote free radical polymerization in mild conditions (e.g., low light intensity, under air). Here, our actual search for new multicomponent photoinitiating systems at 405nm LED prompts us to develop new dyes based on push&ndash, pull structures. In the present paper, we chose two series of new dyes which possess indane-1,3-dione and 1H-cyclopenta naphthalene-1,3-dione groups as the electron-withdrawing groups, since they have the great potential to behave as sensitive and remarkable photoinitiators in vat photopolymerization/3D printing. When incorporated with a tertiary amine (ethyl dimethylaminobenzoate EDB, used as electron/hydrogen donor) and an iodonium salt (used as electron acceptor) as the three-component photoinitiating systems (PISs), and among a series of 21 dyes, 10 of them could efficiently promote the free radical photopolymerization of acrylates. Interestingly, steady state photolysis experiments revealed different behaviors of the dyes. Fluorescence experiments and free energy change calculations for redox processes were also carried out to investigate the relevant chemical mechanisms. Additionally, the formation of radicals from the investigated PISs was clearly observed by electron spin resonance (ESR) spin-trapping experiments. Finally, stereoscopic 3D patterns were successfully fabricated by the laser writing technique. In this work, the use of push&ndash, pull dyes based on the naphthalene scaffold as photoinitiators of polymerization is reported for the first time in a systematic study aiming at investigating the structure&ndash, performance relationship for irradiation carried out at 405 nm. By carefully selecting the electron donors used in the two series of push&ndash, pull dyes, novel and high-performance photoinitiating systems operating at 405 nm are thus proposed.

Published
2020
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18. Chiral Fidelity in the Diastereoselective and Enantiospecific Synthesis of Indenes from Axially Chiral Benzylidene Cyclanes

Author

Aura Tintaru, Frédéric Dumur, Didier Siri, Dominique Mouysset, Nicolas Vanthuyne, Marion Jean, Malek Nechab, Michèle P. Bertrand, Cyril Tessonnier, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires de Marseille (ISM2), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)

Subjects
010405 organic chemistry, Chemistry, Stereochemistry, Organic Chemistry, [CHIM]Chemical Sciences, General Chemistry, 010402 general chemistry, Chirality (chemistry), Axial symmetry, 01 natural sciences, Catalysis, 0104 chemical sciences
Abstract

International audience; Enantioenriched indenes were reached through a chirality conversion strategy using original axially chiral benzylidene cyclanes. Good to high remote diastereocon-trol and excellent enantiocontrol were observed in this cascade involving copper-catalyzed homologation of terminal alkynes, in situ allenoate formation and Alder-ene cyclization.

Published
2017
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19. Unprecedented Nucleophilic Attack of Piperidine on the Electron Acceptor during the Synthesis of Push-Pull Dyes by a Knoevenagel Reaction

Author

Malek Nechab, Frédéric Dumur, Sylvain Duval, Corentin Pigot, Didier Gigmes, Sébastien Péralta, Guillaume Noirbent, Institut de Chimie Radicalaire (ICR), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Aix Marseille Université (AMU), Laboratoire de Physico-chimie des Polymères et des Interfaces (LPPI), Fédération INSTITUT DES MATÉRIAUX DE CERGY-PONTOISE (I-MAT), Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille, Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017), and ANR-17-CE08-0054,VISICAT,Nouveaux Photocatalyseurs Redox pour la Synthèse sous Lumière Visible de Réseaux Polymères Interpénétrés(2017)

Subjects
electron acceptors, Electron donor, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, Biochemistry, Catalysis, Inorganic Chemistry, chemistry.chemical_compound, Nucleophile, Drug Discovery, electron donors, [CHIM]Chemical Sciences, piperidines, Physical and Theoretical Chemistry, Push pull, chemistry.chemical_classification, Chemistry, Organic Chemistry, Electron acceptor, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Knoevenagel reaction, Knoevenagel condensation, Piperidine, 0210 nano-technology, push-pull systems
Abstract

WOS:000497883600001; International audience; An unprecedented nucleophilic addition of piperidine on an electron acceptor, namely, 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene)malononitrile is reported. This unexpected behavior was observed during the synthesis of push-pull dyes using the classical Knoevenagel reaction. To overcome this drawback, use of diisopropylethylamine (DIPEA) enabled to produce the expected dyes PP1 and PP2. The optical and electrochemical properties of the different dyes were examined. Theoretical calculations were also carried out to support the experimental results. To evidence the higher electron-withdrawing ability of this electron acceptor, a comparison was established with two dyes (PP3 and PP4) comprising its shorter analogue.

Published
2019
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20. Diethoxyacetate Salts as Co-initiators for Radical Photosensitive Resins: Towards Aromatic Amine-Free Systems?

Author

Assi Al Mousawi, Malek Nechab, Jean-Pierre Fouassier, Jacques Lalevée, Frédéric Dumur, Akram Hijazi, Mira Abdallah, Institut de Science des Matériaux de Mulhouse (IS2M), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université Libanaise, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Gigmes, Didier

Subjects
chemistry.chemical_classification, [CHIM.POLY] Chemical Sciences/Polymers, Chemistry, Organic Chemistry, Radical polymerization, Aromatic amine, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Photochemistry, 01 natural sciences, 0104 chemical sciences, Analytical Chemistry, [CHIM.POLY]Chemical Sciences/Polymers, Polymerization, Physical and Theoretical Chemistry, 0210 nano-technology, Visible spectrum
Abstract

WOS:000495969700014; International audience; Diethoxyacetate salts are investigated as new co-initiators for the free radical polymerization (FRP) of (meth)acrylates upon visible light exposure, with light emitting diodes (LEDs; 405 nm, 477 nm) being employed for this purpose. Interestingly, the impact of the counter cation on their initiating ability is clearly highlighted. When these co-initiators are combined with commercial photoinitiators such as 2-isopropylthioxanthone (ITX) or camphorquinone (CQ), good to excellent free radical polymerization initiating performances are found and high final reactive function conversions are achieved. In the absence of these co-initiators, no or poor polymerization occurs, clearly highlighting the importance of these co-initiators for an efficient process. These systems can be interesting for the replacement of aromatic amines opening the way for amine-free Type II photoinitiating systems.

Published
2019
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21. Monocomponent Photoinitiators based on Benzophenone-Carbazole Structure for LED Photoinitiating Systems and Application on 3D Printing

Author

Fabrice Morlet-Savary, Malek Nechab, Ke Sun, Shaohui Liu, Pu Xiao, Guillaume Noirbent, Damien Brunel, Yangyang Xu, Hong Chen, Jacques Lalevée, Frédéric Dumur, Didier Gigmes, Bernadette Graff, Yijun Zhang, Corentin Pigot, Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Australian National University (ANU), ANR-17-CE08-0010,DUALITY,Elaboration de réseaux covalents bidimensionnels nanoporeux dirigés par la surface(2017), ANR-17-CE08-0054,VISICAT,Nouveaux Photocatalyseurs Redox pour la Synthèse sous Lumière Visible de Réseaux Polymères Interpénétrés(2017), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), and Dumur, Frederic

Subjects
[CHIM.POLY] Chemical Sciences/Polymers, Polymers and Plastics, Substituent, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, Article, lcsh:QD241-441, chemistry.chemical_compound, monocomponent photoinitiator, lcsh:Organic chemistry, carbazole, Benzophenone, Moiety, Carbazole, Cationic polymerization, 3D printing, General Chemistry, 021001 nanoscience & nanotechnology, 3. Good health, 0104 chemical sciences, [CHIM.POLY]Chemical Sciences/Polymers, Photopolymer, chemistry, Polymerization, 0210 nano-technology, Photoinitiator, benzophenone
Abstract

In this article, different substituents (benzoyl, acetyl, styryl) are introduced onto the carbazole scaffold to obtain 8 novel carbazole derivatives. Interestingly, a benzoyl substituent, connected to a carbazole group, could form a benzophenone moiety, which composes a monocomponent Type II benzophenone-carbazole photoinitiator (PI). The synergetic effect of the benzophenone moiety and the amine in the carbazole moiety is expected to produce high performance photoinitiating systems (PISs) for the free radical photopolymerization (FRP). For different substituents, clear effects on the light absorption properties are demonstrated using UV-Visible absorption spectroscopy. Benzophenone-carbazole PIs can initiate the FRP of acrylates alone (monocomponent Type II photoinitiator behavior). In addition, fast polymerization rates and high function conversions of acrylate are observed when an amine and/or an iodonium salt are added in systems. Benzophenone-carbazole PIs have good efficiencies in cationic photopolymerization (CP) upon LED @ 365 nm irradiation in the presence of iodonium salt. In contrast, other PIs without synergetic effect demonstrate unsatisfied photopolymerization profiles in the same conditions. The best PIS identified for the free radical photopolymerization were used in three-dimensional (3D) printing. Steady state photolysis and fluorescence quenching experiments were carried out to investigate the reactivity and the photochemistry and photophysical properties of PIs. The free radicals, generated from the studied PISs, are detected by the electron spin resonance - spin trapping technique. The proposed chemical mechanisms are provided and the structure/reactivity/efficiency relationships are also discussed. All the results showed that the benzophenone-carbazole PIs have a good application potential, and this work provides a rational design route for PI molecules. Remarkably, BPC2-BPC4, C6, C8 were never synthetized before, therefore, 5 of the 8 compounds are completely new.

Published
2020
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22. Stable copper acetylacetonate-based oxidizing agents in redox (NIR photoactivated) polymerization: an opportunity for the one pot grafting from approach and an example on a 3D printed object

Author

Patxi Garra, Frédéric Dumur, Fabrice Morlet-Savary, Jacques Lalevée, Jean-Pierre Fouassier, Bernadette Graff, Malek Nechab, Céline Dietlin, Didier Gigmes, Institut de Science des Matériaux de Mulhouse (IS2M), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Polymers and Plastics, initiating systems, Radical polymerization, photopolymerization processes, chemistry.chemical_element, Bioengineering, 02 engineering and technology, 010402 general chemistry, Photochemistry, Methacrylate, chemistry, 01 natural sciences, Biochemistry, Redox, composites, Oxidizing agent, Moiety, [CHIM]Chemical Sciences, polymers, chemistry.chemical_classification, Organic Chemistry, technology, industry, and agriculture, confocal raman microscopy, shadow areas, Polymer, 021001 nanoscience & nanotechnology, Copper, 0104 chemical sciences, Polymerization, resins, 0210 nano-technology, photoinitiating systems, complex
Abstract

WOS:000430933900013; The use of new stable copper acetylacetonates in combination with specific bidentate ligands (e.g. 2dppba) is proposed for redox free radical polymerization (FRP) under mild reaction conditions (under air and at room temperature). These systems show high performances so that they can compete with the well-established reference redox initiating systems based on the amine/benzoylperoxide combination. Remarkably, some of our systems are also highly efficient when excited in the near infrared region (NIR), demonstrating that our redox systems can also be activated by light. Using this strategy, the initial redox free radical polymerization could be converted into a redox photoactivated one. More interestingly, a stable copper methacryloyloxy-ethylacetoacetate (Cu(AAEMA)(2)) bearing a reactive methacrylate function and a copper acetylacetonate moiety could be used to polymerize a first polymer layer onto which a second polymerization could be carried out. Precisely , the second polymerization was initiated by a redox process using mild reaction conditions (at room temperature and under air), different from the process used to form the underlayer. To the best of our knowledge, this re-initiation of polymerization from a pre-polymerized layer by a second polymerization technique is highly original and is of crucial industrial/academic interest as no high energy consumption/harmful wavelengths are required to reinitiate the polymerization. The efficiency of this strategy is illustrated by grafting from a 3D printed object.

Published
2018
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23. Organocopper triggered cyclization of conjugated dienynes via tandem S N 2′/Alder-ene reaction

Author

Cyril Borie, Marion Jean, Nicolas Vanthuyne, Michèle P. Bertrand, Malek Nechab, Didier Siri, Tanzeel Arif, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires de Marseille (ISM2), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Tandem, 010405 organic chemistry, Chemistry, Stereochemistry, Organic Chemistry, Substrate (chemistry), Conjugated system, 010402 general chemistry, 01 natural sciences, Combinatorial chemistry, 0104 chemical sciences, Catalysis, Reagent, SN2 reaction, [CHIM]Chemical Sciences, Chirality (chemistry), Ene reaction
Abstract

International audience; Propargylic carbonates were converted to indenes through a S N 2'/Alder-ene cascade triggered by organocopper reagents. The reaction tolerates different organocopper species generated either from organolithiums or Grignard reagents. A catalytic version of this strategy could be devised using either copper or iron catalysts. Attempts to transfer chirality from an enantioenriched substrate revealed a moderate chirality conversion because of a low discrimination between the two faces of the internal olefinic partner with these typical substrates. The theoretical investigation supports a concerted closed-shell mechanism and highlights the influence of the substituents on the activation parameters and on the synchronicity of C-H bond breaking and CC bond forming during the Alder-ene step.

Published
2018
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24. Peroxide-Free and Amine-Free Redox Free Radical Polymerization: Metal Acetylacetonates/Stable Carbonyl Compounds for Highly Efficient Synthesis of Composites

Author

Didier Gigmes, Evgeniya P. Doronina, Jacques Lalevée, Valery F. Sidorkin, Jean Pierre Fouassier, Céline Dietlin, Bernadette Graff, Patxi Garra, Malek Nechab, Frédéric Dumur, Fabrice Morlet-Savary, Institut de Science des Matériaux de Mulhouse (IS2M), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), A.E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences (SB RAS), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
translucent fiberglass post, dental resins, Polymers and Plastics, initiating systems, Radical polymerization, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, Peroxide, Redox, law.invention, Inorganic Chemistry, chemistry.chemical_compound, law, Materials Chemistry, [CHIM]Chemical Sciences, Electron paramagnetic resonance, manganese tris(acetylacetonate)-acetic acid, ligand interaction mabli, Spin trapping, Organic Chemistry, confocal raman microscopy, shadow areas, 021001 nanoscience & nanotechnology, organic halides, 0104 chemical sciences, Monomer, chemistry, Polymerization, Metal acetylacetonates, 0210 nano-technology, monitoring photopolymerization reactions, alkyd paints
Abstract

WOS:000443524600024; New peroxide-free, amine-free, and phosphine-free redox free radical polymerization (RFRP) initiating systems comprising remarkably stable (i) metal acetylacetonates (Mn(acac)(3), Cu(acac)(2)) and (ii) carbonyl compounds bearing labile hydrogen in the alpha-position are presented for polymerization initiation under mild conditions (under air, at room temperature, nonpurified monomers). The systems proposed in this work are competitive or even outranked the well-known peroxide-based RFRP reference in several criteria: (i) toxicity, (ii) stability, (iii) surface curing, (iv) overall double-bond conversions, and (v) workability of the RFRP mixture (longer gel times are now possible). Radical initiating reactions are studied using many complementary experimental/theoretical techniques: optical pyrometry, thermal imaging, Raman confocal microscopy, electron spin resonance (ESR), ESR spin trapping (ESR-ST), high-resolution electrospray ionization mass spectrometry ( HR-ESI-MS), density functional theory (DFT), simulations of bond dissociation energies (BDE), reaction enthalpies, and DFT simulations of seven unknown ESR-ST adducts. A full consistent picture of the chemical mechanisms involved in these new redox systems is provided.

Published
2018
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25. Metal Acetylacetonate-Bidentate Ligand Interaction (MABLI) (Photo)activated Polymerization: Toward High Performance Amine-Free, Peroxide-Free Redox Radical (Photo)initiating Systems

Author

Malek Nechab, Frédéric Dumur, Céline Dietlin, Didier Gigmes, Fabrice Morlet-Savary, Patxi Garra, Jacques Lalevée, Simon Gree, Jean Pierre Fouassier, Institut de Science des Matériaux de Mulhouse (IS2M), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
dental resins, Polymers and Plastics, Radical, initiating systems, Radical polymerization, photopolymerization processes, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, Peroxide, Redox, Inorganic Chemistry, chemistry.chemical_compound, Materials Chemistry, [CHIM]Chemical Sciences, Aryl, Organic Chemistry, Cationic polymerization, confocal raman microscopy, shadow areas, 021001 nanoscience & nanotechnology, 0104 chemical sciences, reactivity, Photopolymer, chemistry, Polymerization, cationic-polymerization, oxygen inhibition, 0210 nano-technology, photoinitiating systems, 3d printing resins
Abstract

WOS:000430022000031; Free radical polymerization (FRP) initiation from metal acetylacetonate-bidentate ligand interaction (MABLI) under mild conditions (room temperature, under air) is discussed here for different metal centers (Mn, V, and Cu). First, without light, in MABLI systems such as V(acac)(3)/2-diphenylphosphinobenzoic acid (2dppba), Mn(acac)(3)/2dppba, or Cu(acac)(2)/2dppba, electron-rich aryl (Ar-center dot) radicals were conveniently and efficiently produced by the reaction of electron-poor acac(center dot) radicals with the iodonium salt (Iod), leading to an enhancement of pure redox (no light) polymerizations. Second, it was found that V(III)*/Iod reaction is generating aryl (Ar-center dot) radicals at a high enough rate to initiate a photopolymerization process upon mild irradiation (LED@405 nm). This reaction can be implemented in redox photoactivated systems (e.g., using three-component V(acac)(3)/2dppba/Iod systems) in order to spectacularly enhance a slow redox process from 40 degrees C exothermicity in 800 s to 93 degrees C in less than 200 s. Third, an impressive chemical bleaching (without light) was reported for the Mn(acac)(3)/2dppba reaction. Photoactivation of the Mn(acac)(3)/2dppba/Iod system led to outstanding FRP initiation efficiencies (\textless20 s for more than 85% C=C conversion of a low-viscosity methacrylate resin). Light enhancement of surface curing was confirmed for all the redox photoactivated polymerizations using Raman confocal microscopy. Overall, amine-free peroxide-free MABLI radical initiating systems were highly improved for safer and even more efficient redox (photoactivated) polymerizations. This original combination of redox polymerization and photopolymerization will be highly worthwhile to combine in one approach the advantages of both techniques.

Published
2018
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26. Enediynes bearing polyfluoroaryl sulfoxide as new antiproliferative agents with dual targeting of microtubules and DNA

Author

Hugo Lingua, Cendrine Nicoletti, Cyril Borie, Tanzeel Arif, Viviane Robert, Shovan Mondal, Malek Nechab, Manon Briand, Marc Maresca, Frédéric Dumur, Daniel Olive, Bernadette Barbarat, Pierre Stocker, Didier Gigmes, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Syamsundar College, Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC), Institut des Sciences Moléculaires de Marseille (ISM2), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Immunologie des Tumeurs, Université de la Méditerranée - Aix-Marseille 2-Institut Paoli-Calmettes, and Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)

Subjects
Ultraviolet Rays, Antineoplastic Agents, [CHIM.THER]Chemical Sciences/Medicinal Chemistry, 010402 general chemistry, 01 natural sciences, Microtubules, chemistry.chemical_compound, Dna cleavage, Microtubule, Prostate, Pancreatic cancer, Cell Line, Tumor, Drug Discovery, medicine, Humans, DNA Breaks, Double-Stranded, Pharmacology, Kidney, DNA cleavage, 010405 organic chemistry, Organic Chemistry, Sulfoxide, General Medicine, DNA, medicine.disease, 0104 chemical sciences, 3. Good health, medicine.anatomical_structure, Anticancer, chemistry, Sulfoxides, Cancer research, Enediynes, Pancreas, light activation
Abstract

International audience; A novel series of enediynes possessing pentafluorophenylsulfoxide have been developed. The innovative compounds possess antiproliferative activity against a broad panel of human cancer cells originating from breast, blood, lung, kidney, colon, prostate, pancreas or skin with IC 50 ranging from 0.6 to 3.4 µM. The antiproliferative activity of enediynes in darkness is associated to their ability to compromise microtubule network. In addition, exposure to UV leads to double-stranded DNA cleavage caused by the newly synthesized molecules reducing further their IC 50 in nanomolar range against human tumor cells, including chemo-resistant pancreatic cancer cells. Taken together, the examined data demonstrate that enediynes possessing pentafluorosulfoxide are promising molecules in the cancer therapy.

Published
2017
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27. Double Transfer of Chirality in Organocopper-Mediated bis(Alkylating) Cycloisomerization of Enediynes

Author

Malek Nechab, Dominique Mouysset, Nicolas Vanthuyne, Michèle P. Bertrand, Cyril Borie, Tanzeel Arif, Jean-Valère Naubron, Damien Campolo, Chimie, biologie et radicaux libres - UMR 6517 (CBRL), Université de la Méditerranée - Aix-Marseille 2-Université Paul Cézanne - Aix-Marseille 3-Université de Provence - Aix-Marseille 1-Centre National de la Recherche Scientifique (CNRS), Spectropôle - Aix Marseille Université (AMU SPEC), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), and Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
inorganic chemicals, 010405 organic chemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Chemistry, Stereochemistry, organic chemicals, Enantioselective synthesis, General Medicine, General Chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, 3. Good health, Enantiopure drug, Cycloisomerization, Reagent, health occupations, polycyclic compounds, heterocyclic compounds, Chirality (chemistry), ComputingMilieux_MISCELLANEOUS
Abstract

An original synthesis of chiral benzofulvenes triggered by organocopper reagents is reported. These enantiopure products are available through a highly chemo-, regio-, diastereo-, and enantioselective bis(alkylating) cycloisomerization process. A double chirality transfer (central-to-axial-to-central) is observed.

Published
2014
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28. Cooperative Use of VCD and XRD for the Determination of Tetrahydrobenzoisoquinolines Absolute Configuration: A Reliable Proof of Memory of Chirality and Retention of Configuration in Enediyne Rearrangements

Author

Jean-Valère Naubron, Michèle P. Bertrand, Michel Giorgi, Shovan Mondal, Damien Campolo, and Malek Nechab

Subjects
Pharmacology, Diffraction, 010405 organic chemistry, Chemistry, Organic Chemistry, Absolute configuration, 010402 general chemistry, Photochemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Analytical Chemistry, law.invention, Crystallography, law, Drug Discovery, Vibrational circular dichroism, X-ray crystallography, Enediyne, Chirality (chemistry), Walden inversion, Single crystal, Spectroscopy
Abstract

The absolute configurations (AC) of azaheterocylic compounds resulting from the cascade rearrangement of enediynes involving only light atoms were unambiguously assigned by the joint use of vibrational circular dichroism (VCD) and copper radiation single crystal X-ray diffraction (XRD). These AC determinations proved that the rearrangements of enediynes proceeded with memory of chirality and retention of configuration. Chirality 25:832-839, 2013. (c) 2013 Wiley Periodicals, Inc.

Published
2013
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29. ChemInform Abstract: Enantioselective Syntheses of Indanes: From Organocatalysis to C-H Functionalization

Author

Malek Nechab, Cyril Borie, and Lutz Ackermann

Subjects
Chemistry, Organocatalysis, Enantioselective synthesis, Surface modification, 02 engineering and technology, General Medicine, 010402 general chemistry, 021001 nanoscience & nanotechnology, 0210 nano-technology, 01 natural sciences, Combinatorial chemistry, 3. Good health, 0104 chemical sciences
Abstract

The indanyl core is ubiquitous in a large variety of drugs and natural products. Importantly, the ever-increasing demand for chiral catalysts bearing this scaffold calls for state of the art methods allowing for a step-economical enantioselective access to this structural motif. We herein summarize the asymmetric syntheses of indanes with a particular focus on asymmetric catalysis, covering the literature of the last decade until July 2015.

Published
2016
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30. ChemInform Abstract: Organocopper-Triggered Cyclization of Conjugated Diene-ynes: Diastereo- and Enantioselective Synthesis of Indenes

Author

Nicolas Vanthuyne, Malek Nechab, Tanzeel Arif, Jean-Valère Naubron, Cyril Borie, Aura Tintaru, and M. P. Bertrand

Subjects
Chemistry, Stereochemistry, Enantioselective synthesis, Conjugated diene, General Medicine, Stereocenter
Abstract

A new method for the construction of chiral indenes bearing two stereogenic centers is developed.

Published
2016
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31. Palladium Tandem Catalysis in the Atropodiastereoselective Synthesis of Indenes Bearing Central and Axial Chirality

Author

Nicolas Vanthuyne, Malek Nechab, Michèle P. Bertrand, Cyril Borie, Didier Siri, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires de Marseille (ISM2), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Atropisomer, boronic acids, Tandem, ene-allenes, 010405 organic chemistry, Stereochemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, atropisomers, chemistry.chemical_element, General Chemistry, indenes, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Stereocenter, cascade, chemistry, Axial chirality, remote diastereocontrol, Intramolecular force, palladium catalysis, Alder-ene, Palladium
Abstract

International audience; The conversion of propargylic carbonates into allenes via Pd-catalyzed coupling with arylboronic acids, followed by tandem intramolecular Alder-ene cyclization, proceeds with remote diastereocontrol in the formation of indenes possessing two stereogenic elements (stereocenter and chiral axis). Highly configurationally stable atropisomers have been obtained with dr values up to >98:2. The reaction tolerates a range of commercially available functionalized arylboronic acids and allows the creation of C(sp2)–C(sp2) and C(sp2)–C(sp3) bonds in a single operation. Control experiments suggest that synergetic thermal and Pd-catalyzed cyclizations are likely to be involved in the second elementary step.

Published
2016
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32. Enantioselective syntheses of indanes: from organocatalysis to C-H functionalization

Author

Malek Nechab, Cyril Borie, Lutz Ackermann, FEE Froschunginstitut für mineralische un metallische Werkstoffe-Edelsteine/Edelmetalle, Institut de Chimie Radicalaire (ICR), and Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010405 organic chemistry, Chemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Enantioselective synthesis, Molecular Conformation, Nanotechnology, Stereoisomerism, General Chemistry, 010402 general chemistry, 01 natural sciences, Combinatorial chemistry, Catalysis, 0104 chemical sciences, 3. Good health, Organocatalysis, Indans, Surface modification, Organic Chemicals, ComputingMilieux_MISCELLANEOUS
Abstract

The indanyl core is ubiquitous in a large variety of drugs and natural products. Importantly, the ever-increasing demand for chiral catalysts bearing this scaffold calls for state of the art methods allowing for a step-economical enantioselective access to this structural motif. We herein summarize the asymmetric syntheses of indanes with a particular focus on asymmetric catalysis, covering the literature of the last decade until July 2015.

Published
2016
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33. Synthesis of Enantiopure Tertiary Skipped Diynes via One-Pot Desymmetrizing TMS-Cleavage

Author

Nicolas Vanthuyne, Malek Nechab, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires de Marseille (ISM2), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Amino esters, 010405 organic chemistry, Chemistry, Stereochemistry, Organic Chemistry, Methoxide, 010402 general chemistry, Cleavage (embryo), 01 natural sciences, Biochemistry, 0104 chemical sciences, chemistry.chemical_compound, Enantiopure drug, [CHIM]Chemical Sciences, Chelation, Physical and Theoretical Chemistry
Abstract

International audience; Enantiopure tetrasubstituted skipped diynes were readily synthesized from N-protected amino esters upon addition of lithium TMS-acetylide which was found to be desymmetrizing through one-pot selective TMS-cleavage. The deprotection of the TMS group was realized through a one-pot silicon atom attack by the liberated methoxide, which was diastereoselective due to a conformational favorable chelate.

Published
2012
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34. Copper Carbenoid, Reactant and Catalyst for One-Pot Diazo Ester Coupling Cascade Rearrangement of Enediynes: Formation of Two Contiguous Tetrasubstituted Stereocenters

Author

Nicolas Vanthuyne, Malek Nechab, Michèle P. Bertrand, Damien Campolo, Shovan Mondal, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires de Marseille (ISM2), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Amino esters, 010405 organic chemistry, Stereochemistry, General Chemistry, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 3. Good health, 0104 chemical sciences, Catalysis, Stereocenter, chemistry.chemical_compound, chemistry, [CHIM]Chemical Sciences, Diazo, Chirality (chemistry), Isomerization, Carbenoid, Ene reaction
Abstract

International audience; The copper-catalyzed reaction of enediynes with diazo esters leads to cyclic amino esters bearing two contiguous tetrasubstituted stereogenic centers through a one-pot, five-step cascade. Copper iodide catalyzes the formation of an intermediate 3-alkynoate and copper carbenoid promotes its reversible isomerization to the corresponding allenoate. The alkynoate-allenoate equilibrium is completely shifted to the right by the rapid consumption of the allenoate by MyersSaito cyclization. This is followed by 1,5-H atom transfer and recombination of the resulting biradical. Memory of chirality phenomenon explains the high enantioselectivity.

Published
2012
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35. Organocopper-Triggered Cyclisation of Conjugated Diene-ynes: Diastereo- and Enantioselective Synthesis of Indenes

Author

Nicolas Vanthuyne, Aura Tintaru, Michèle P. Bertrand, Cyril Borie, Jean-Valère Naubron, Tanzeel Arif, Malek Nechab, Spectropôle - Aix Marseille Université (AMU SPEC), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Institut des Sciences Moléculaires de Marseille (ISM2), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, Addition reaction, 010405 organic chemistry, Alkene, Stereochemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Enantioselective synthesis, General Chemistry, Conjugated system, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Stereocenter, chemistry.chemical_compound, chemistry, Reagent, [CHIM]Chemical Sciences, Indene, Chirality (chemistry)
Abstract

International audience; Organocopper reagents react with readily available chiral conjugated diene-ynes to give indene derivatives bearing two stereogenic centres. The investigation of this original reaction in optically pure series demonstrates that a double transfer of chirality is operating. A stereocontrolled cascade involving S(N)2' followed by carbocupration and conjugate addition reactions accounts for the total recovery of the initial chirality. The scope and limitations of the reaction were investigated. The high diastereofacial discrimination in the cyclisation step allowed the construction of the quaternary stereocentre with excellent dr and ee, with the opposite configuration depending on the E- or Z-configuration of the alkene in the starting material. Post-functionalisation of indenes allowed the synthesis of indanyl derivatives containing four contiguous stereocentres.

Published
2015
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36. ChemInform Abstract: 1,n-Hydrogen-Atom Transfer (HAT) Reactions in Which n ≠ 5: An Updated Inventory

Author

Michèle P. Bertrand, Malek Nechab, and Shovan Mondal

Subjects
Chemistry, Computational chemistry, Intramolecular force, Radical, Regioselectivity, General Medicine, Hydrogen atom
Abstract

Hydrogen-atom transfer (HAT) counts amongst the most widely investigated routes to carbon-centered radicals. Intramolecular processes involving 1,5-HAT are widespread to promote regioselective radical "CH activation". The aim of this review is to draw up a comprehensive inventory of the less commonly encountered 1,n-radical translocations (n≠5) with the aim to update this topic with the most recent relevant data.

Published
2015
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37. A Single-Step Synthesis of Symmetrical 1,3-Diarylisobenzofurans

Author

Cathy Einhorn, Jacques Einhorn, Malek Nechab, and Farah Benderradji

Subjects
Nucleophilic addition, Isobenzofuran, Chemistry, Aryl, fungi, Organic Chemistry, Single step, General Medicine, Combinatorial chemistry, Adduct, chemistry.chemical_compound, Reagent, Organic chemistry, Maleimide
Abstract

A convenient single-step synthesis of various symmetrically substituted 1,3-diarylisobenzofiirans from readily available 3-methoxy-3H-isobenzofuran-l-one (la) and two equivalents of aryl Grignard reagents is described. The title compounds are obtained in medium to high isolated yields. Crude isobenzofuran has also been trapped by maleimide, furnishing pure Diels-Alder adduct almost quantitatively.

Published
2006
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38. Efficient chromatographic resolution of a configurationally fragile atropisomeric diphenol via its N-(α)-Boc-tryptophan diesters

Author

Cathy Einhorn, Jacques Einhorn, Christian Philouze, Bhavesh M. Panchal, and Malek Nechab

Subjects
Chromatography, Stereochemistry, Chemistry, Organic Chemistry, Absolute configuration, Diastereomer, Cleavage (embryo), Catalysis, Stereocenter, Inorganic Chemistry, Yield (chemistry), Physical and Theoretical Chemistry, Enantiomer, Single crystal, Isomerization
Abstract

Racemic 4,5-bis-(2-hydroxy-phenyl)-benzo[f]isoindole-1,3-dione 2, an atropisomeric diphenol prone to thermal isomerisation, has been efficiently resolved by conversion into its N-(α)-Boc-tryptophan diesters. Easy chromatographic separation of the diastereomeric pair of diesters, followed by ester cleavage under mild conditions gave each enantiomer in good yield and high enantiomeric purity. X-ray diffraction on a single crystal of one of the diastereomeric diesters allowed attribution of the absolute configuration of the stereogenic axes.

Published
2005
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40. Enantioselective Synthesis of Carbocycles and Heterocycles by Radical/Polar and Polar/Radical Cascades

Author

Michèle P. Bertrand, Shovan Mondal, Malek Nechab, Institut de Chimie Radicalaire (ICR), and Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010405 organic chemistry, Chemistry, Radical, Enantioselective synthesis, [CHIM]Chemical Sciences, Polar, Organic chemistry, General Chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences
Abstract

nly twenty years ago, enantioselective synthesis, involvingradical intermediates, was still regarded as rather limited.However, the knowledge of the parameters essential forstereocontrol and the use of chiral auxiliaries in radicalreactions had already reached a very high level of develop-ment. Another breakthrough came from the work of Porter,Sibi, and co-workers with the introduction of chiral Lewisacids.

Published
2012
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41. 1, n -Hydrogen-Atom Transfer (HAT) Reactions in Which n ≠5: An Updated Inventory

Author

Malek Nechab, Michèle P. Bertrand, Shovan Mondal, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Trivedi science research laboratory pvt. Ltd.

Subjects
010405 organic chemistry, Chemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Radical, Organic Chemistry, Regioselectivity, General Chemistry, Hydrogen atom, 010402 general chemistry, Photochemistry, 01 natural sciences, Catalysis, 3. Good health, 0104 chemical sciences, Intramolecular force, ComputingMilieux_MISCELLANEOUS
Abstract

Hydrogen-atom transfer (HAT) counts amongst the most widely investigated routes to carbon-centered radicals. Intramolecular processes involving 1,5-HAT are widespread to promote regioselective radical "CH activation". The aim of this review is to draw up a comprehensive inventory of the less commonly encountered 1,n-radical translocations (n≠5) with the aim to update this topic with the most recent relevant data.

Published
2014
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42. ChemInform Abstract: Double Transfer of Chirality in Organocopper-Mediated Bis(alkylating) Cycloisomerization of Enediynes

Author

Damien Campolo, Dominique Mouysset, Cyril Borie, Nicolas Vanthuyne, Tanzeel Arif, Jean-Valère Naubron, Michèle P. Bertrand, and Malek Nechab

Subjects
Cycloisomerization, Chemistry, Stereochemistry, Enantioselective synthesis, General Medicine, Chirality (chemistry)
Abstract

The synthesis of chiral benzofulvenes, triggered by organocopper reagents, is achieved through a highly chemo-, regio-, diastereo-, and enantioselective bis(alkylating) cycloisomerization process.

Published
2014
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43. Theoretical study to explain how chirality is stored and evolves throughout the radical cascade rearrangement of enyne-allenes

Author

Malek Nechab, Damien Campolo, Michèle P. Bertrand, Didier Siri, Anouk Gaudel-Siri, Shovan Mondal, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Trivedi science research laboratory pvt. Ltd., and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Molecular Structure, Enyne, Diradical, Chemistry, Stereochemistry, Organic Chemistry, Stereoisomerism, Hydrogen atom, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, Models, Theoretical, Stereocenter, Alkadienes, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Cyclization, Cascade, Computational chemistry, Alkynes, Intramolecular force, Singlet state, Chirality (chemistry), ComputingMilieux_MISCELLANEOUS
Abstract

International audience; This article reports a theoretical study to explain how the intrinsic property of chirality is retained throughout the radical cascade rearrangement of an enantiopure chiral enyne-allene (bearing one stereogenic center) selected as a model for this family of reactions. Calculations at the MRPT2/6-31G(d)//CASSCF(10,10)/6-31G(d) level of theory were used to determine the entire reaction pathway which includes singlet state diradicals and closed-shell species. The cascade process involves three elementary steps, i.e., by chronological order: Myers–Saito cycloaromatization (M-S), intramolecular hydrogen atom transfer (HAT), and recombination of the resulting biradical. The enantiospecificity of the reaction results from a double transmission of the stereochemical information, from the original center to an axis and eventually from this axis to the final center. The first two steps lead to a transient diradical intermediate which retains the chirality via the conversion of the original static chirogenic element into a dynamic one, i.e., a center into an axis. The only available routes to the final closed-shell tetracyclic product imply rotations around two σ bonds (σ(C–C) and σ(C–N), bonds β and α respectively). The theoretical calculations confirmed that the formation of the enantiomerically pure product proceeds via the nonracemizing rotation around the σ(C–C) pivot. They ruled out any rotation around the second σ(C–N) pivot. The high level of configurational memory in this rearrangement relies on the steric impediment to the rotation around the C–N bond in the chiral native conformation of the diradical intermediate produced from tandem M-S/1,5-HAT.

Published
2014
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44. En Route to (S)-Selective Chemoenzymatic Dynamic Kinetic Resolution of Aliphatic Amines. One-Pot KR/Racemization/KR Sequence Leading to (S)-Amides

Author

Michèle P. Bertrand, Nicolas Vanthuyne, Stéphane Gastaldi, Lahssen El Blidi, Gérard Gil, and Malek Nechab

Subjects
Chemistry, medicine.drug_class, Organic Chemistry, medicine, Organic chemistry, Amine gas treating, Carboxamide, Selectivity, Enantiomeric excess, Aliphatic compound, Chemical synthesis, Racemization, Kinetic resolution
Abstract

A one-pot sequential process, involving a radical racemization and an enzymatic resolution, provides access to (S)-amides, from racemic amines, with ee and yields ranging from 78 to 94% and 58 to 80%, respectively.

Published
2009
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46. ChemInform Abstract: Axial-to-Central Chirality Transfer in Cyclization Processes

Author

Michèle P. Bertrand, Stéphane Gastaldi, Damien Campolo, Malek Nechab, and Christian Roussel

Subjects
Enantiopure drug, Axial chirality, Computational chemistry, Chemistry, High Energy Physics::Lattice, General Medicine, Chirality (chemistry), Axial symmetry, Stereocenter
Abstract

Substrates, bearing axial chirality, can cyclize intra- or inter-molecularly with concomitant transfer of axial-to-central chirality to produce at least one stereocenter. In order to satisfy a strict definition of axial-to-central chirality transfer, the initial axial chirality must be lost during the cyclization process. Highly functionalized enantiopure carbocycles and heterocycles were prepared using this strategy. The transformations of configurationally stable substrates take place with high regio- and stereo-selectivity. Selected examples involving allenes, biaryls, arylamides and transient axially chiral short-lived species are discussed. Special attention is focused on the mechanistic rationale of the chirality transfer.

Published
2013
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47. Photoactivated cyclization of aryl-containing enediynes coated gold nanoparticles: enhancement of the DNA cleavage ability of enediynes

Author

Michèle P. Bertrand, Shovan Mondal, Olivier Grauby, Daniel Olive, Didier Gigmes, Malek Nechab, Bernadette Barbarat, Frédéric Dumur, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche en Cancérologie de Marseille (CRCM), Aix Marseille Université (AMU)-Institut Paoli-Calmettes, and Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Absorption spectroscopy, Enediyne, Photochemistry, Metal Nanoparticles, 010402 general chemistry, Ligands, 01 natural sciences, Nanocomposites, chemistry.chemical_compound, Colloid and Surface Chemistry, Dynamic light scattering, Coated Materials, Biocompatible, Microscopy, Electron, Transmission, Gold nanoparticles, Colloids, Physical and Theoretical Chemistry, DNA Cleavage, Bond cleavage, Photolysis, Molecular Structure, 010405 organic chemistry, Chemistry, DNA, Superhelical, Aryl, Surfaces and Interfaces, General Medicine, DNA, [CHIM.MATE]Chemical Sciences/Material chemistry, Photochemical Processes, 0104 chemical sciences, Polymerization, Colloidal gold, Cyclization, DNA supercoil, Gold, Enediynes, Biotechnology
Abstract

International audience; Two novel enediynes containing an aromatic ring and substituted by two thiol functions as end-groups were designed and studied as functionalizing agent of gold nanoparticles. Phototriggered cyclization of the capping agent under UV-visible irradiation was investigated. Interestingly, the length of the thiolsubstituted chain was shown to influence significantly the cyclization rate. Depending on the length of the spacer, either polymerization or simple cyclization of the coating agent was evidenced. The present study underscores the possibility of finely controlling the fate of the coating agent (polymerization/cyclization). Nanocomposites were characterized by UV-visible absorption spectroscopy, dynamic light scattering (DLS) technique and transmission electron microscopy (TEM) measurements. Finally, the ability of the colloidal solutions to induce photoinitiated damages to PcDNA3 supercoiledDNAwas evaluated. Interestingly, an increase as high as 50% of the DNA cleavage could be registered when adding enediynes-capped gold nanoparticles to solutions of enediynes. In particular, the enhancement ofDNAscission was observed in both thermal and photochemical activation modes.

Published
2013
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48. New thiols for photoinitiator free thiol-acrylate polymerization

Author

Jean Pierre Fouassier, Bernadette Graff, Jacques Lalevée, Michèle P. Bertrand, Didier Gigmes, Shovan Mondal, Malek Nechab, Mohamad-Ali Tehfe, Frédéric Dumur, Laboratoire de Photochimie et d'Ingénierie Macromoléculaires (LPIM), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Acrylate, Polymers and Plastics, Chemistry, Organic Chemistry, Photodissociation, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Free thiol, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Resonance (chemistry), Photochemistry, 01 natural sciences, 0104 chemical sciences, chemistry.chemical_compound, Polymerization, Polymer chemistry, Materials Chemistry, Molecular orbital, Physical and Theoretical Chemistry, 0210 nano-technology, Thiyl radicals, Photoinitiator
Abstract

International audience; New thiols for effi cient thiol-ene polymerization reactions are presented. They do not exhibit any unpleasant odor, are characterized by quite good light-absorption properties at λ > 300 nm, and generate thiyl radicals upon UV-light exposure. Due to these interesting properties and contrary to many previously reported methodologies, the present thiol-acrylate polymerizations can be effi ciently carried out without the presence of any additional photoinitiator. The chemical mechanisms are investigated by steady-state photolysis and electron spion resonance (ESR) experiments. Important parameters can also be extracted from molecular orbital calculations

Published
2013
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49. Cooperative use of VCD and XRD for the determination of tetrahydrobenzoisoquinolines absolute configuration: a reliable proof of memory of chirality and retention of configuration in enediyne rearrangements

Author

Shovan, Mondal, Jean-Valère, Naubron, Damien, Campolo, Michel, Giorgi, Michéle P, Bertrand, and Malek, Nechab

Subjects
X-Ray Diffraction, Circular Dichroism, Computer Simulation, Stereoisomerism, Enediynes, Isoquinolines
Abstract

The absolute configurations (AC) of azaheterocylic compounds resulting from the cascade rearrangement of enediynes involving only light atoms were unambiguously assigned by the joint use of vibrational circular dichroism (VCD) and copper radiation single crystal X-ray diffraction (XRD). These AC determinations proved that the rearrangements of enediynes proceeded with memory of chirality and retention of configuration.

Published
2013

50. Axial-to-central chirality transfer in cyclization processes

Author

Stéphane Gastaldi, Christian Roussel, Damien Campolo, Malek Nechab, Michèle P. Bertrand, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires de Marseille (ISM2), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Molecular Structure, 010405 organic chemistry, Chemistry, Stereochemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, High Energy Physics::Lattice, Acids, Carbocyclic, Stereoisomerism, General Chemistry, Silanes, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Stereocenter, Enantiopure drug, Cyclization, Heterocyclic Compounds, Axial chirality, Computational chemistry, Molecule, Chirality (chemistry), Axial symmetry
Abstract

International audience; Substrates, bearing axial chirality, can cyclize intra-or inter-molecularly with concomitant transfer of axial-to-central chirality to produce at least one stereocenter. In order to satisfy a strict definition of axial-to-central chirality transfer, the initial axial chirality must be lost during the cyclization process. Highly functionalized enantiopure carbocycles and heterocycles were prepared using this strategy. The transformations of configurationally stable substrates take place with high regio-and stereo-selectivity. Selected examples involving allenes, biaryls, arylamides and transient axially chiral short-lived species are discussed. Special attention is focused on the mechanistic rationale of the chirality transfer.

Published
2013
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