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Producción Científica, New 1,2-azolylamidino complexes cis-[Ru(bipy)2(NH═C(R)az*-κ2N,N)](OTf)2 (R = Me, Ph; az* = pz, indz, dmpz) are synthesized via chloride abstraction after a subsequent base-catalyzed coupling of a nitrile with the previously coordinated 1,2-azole. The synthetic procedure allows the easy obtainment of complexes having different electronic and steric 1,2-azoylamidino ligands. All of the compounds have been characterized by 1H, 13C, and 15N NMR and IR spectroscopy and by monocrystal X-ray diffraction. Photophysical studies support their phosphorescence, whereas their electrochemistry reveals reversible RuII/RuIII oxidations between +1.13 and +1.25 V (vs SCE). The complexes have been successfully used as catalysts in the photooxidation of different thioethers, the complex cis-[Ru(bipy)2(NH═C(Me)dmpz-κ2N,N)]2+ showing better catalytic performance in comparison to that of [Ru(bipy)3]2+. Moreover, the significant catalytic performance of the dimethylpyrazolylamidino complex is applied to the preparation of the drug modafinil, which is obtained using ambient oxygen as an oxidant. Finally, mechanistic assays suggest that the oxidation reaction follows a photoredox route via oxygen radical anion formation., Ministerio de Economía, Industria y Competitividad (grants PGC2018- 099470-B-I00 and RTI2018-095038-B-I00), Junta de Castilla y León (grant VA130618), Junta de Castilla y León - Fondo Social Europeo (project BU263P18)

The in situ spectroelectrochemical cyclic voltammetric studies of the antimony-monocapped nickel(II) and iron(II) tris-pyridineoximates with a labile triethylantimony cross-linking group and Zr(IV)/Hf(IV) phthalocyaninate complexes were performed in order to understand the nature of the redox events in the molecules of heterodinuclear zirconium(IV) and hafnium(IV) phthalocyaninate-capped derivatives. Electronic structures of their 1e-oxidized and 1e-electron-reduced forms were experimentally studied by electron paramagnetic resonance (EPR) spectroscopy and UV&minus, vis&minus, near-IR spectroelectrochemical experiments and supported by density functional theory (DFT) calculations. The investigated hybrid molecular systems that combine a transition metal (pseudo)clathrochelate and a Zr/Hf-phthalocyaninate moiety exhibit quite rich redox activity both in the cathodic and in the anodic region. These binuclear compounds and their precursors were tested as potential catalysts in oxidation reactions of cyclohexane and the results are discussed.

Substituted imidazolium ionic liquids (ILs) were investigated for their reactivity towards Na12Ge17 as a model system containing redox‐sensitive Zintl cluster anions. The ILs proved widely inert for imidazolium cations with a 1,2,3‐trisubstitution at least by alkyl groups, and for the anion bis(trifluoromethylsulfonyl)azanide (TFSI). A minute conversion of Na12Ge17 observed on long‐time contact with such ILs was not caused by dissolution of the salt‐like compound, and did thus not provide dissolved Ge clusters. Rather, a cation exchange led to the transfer of Na+ ions into solution. In contrast, by using benzophenone as an oxidizer, heterogeneous redox reactions of Na12Ge17 were initiated, transferring a considerable part of Na+ into solution. At optimized conditions, an X‐ray amorphous product NaGe6.25 was obtained, which was thermally convertible to the crystalline type‐II clathrate Na24–δGe136 with almost completely Na‐filled polyhedral cages, and α‐Ge. The presented method thus provides unexpected access to Na24–δGe136 in bulk quantities., High‐purity 1,2,3‐trisubstituted imidazolium [TFSI] ionic liquids were prepared and found inert towards the redox‐sensitive Na12Ge17, making them suitable media for heterogeneous redox reactions. By admixture of benzophenone, Na12Ge17 was oxidized to an X‐ray amorphous product, which proved valuable as a precursor for a thermal conversion to the difficult to access type‐II clathrate Na24–δGe136 with almost completely Na‐filled polyhedral cages.

The selective oxidation of trans-2-hexen-1-ol to the corresponding aldehyde using a recombinant aryl alcohol oxidase from Pleurotus eryngii (PeAAOx) is reported. Especially using the two liquid phase system to overcome solubility and product inhibition issues enabled to achieve more than 2.200.000 catalytic turnovers for the production enzyme as well as molar product concentrations, pointing towards an economic feasible reaction.

We study the reactivity of Fe(IV)O moieties supported by a metal–organic framework (MOF-74) in the oxidation reaction of methane to methanol using all-electron, periodic density-functional theory calculations. We compare results concerning the electronic properties and reactivity obtained using two hybrid (B3LYP and sc-BLYP) and two standard generalised gradient corrected (PBE and BLYP) semi-local density functional approximations. The semi-local functionals are unable to reproduce the expected reaction profiles and yield a qualitatively incorrect representation of the reactivity. Non-local hybrid functionals provide a substantially more reliable description and predict relatively modest (ca. 60 kJ mol−1) reaction energy barriers for the H-atom abstraction reaction from CH4 molecules. We examine the origin of these differences and we highlight potential means to overcome the limitations of standard semi-local functionals in reactivity calculations in solid-state systems., This research was supported in part by the University of Pittsburgh Center for Research Computing through the resources provided and the Supercomputing Center of Galicia (CESGA), Spain.

Encapsulated metalloporphyrins have been widely studied for their use as efficient heterogeneous catalysts, inspired by the known catalytic activity of porphyrins in haemoproteins. The oxidation of organic substrates by haemoproteins is one of the well-known roles of these proteins, in which the haem (ferriprotoporphyrin IX = FePPIX) cofactor is the centre of reactivity. While these porphyrins are highly efficient catalysts in the protein environment, once removed, they quickly lose their reactivity. It is for this reason that they have garnered much interest in the field of heterogeneous catalysis of oxidation reactions. This review details current research in the field, focusing on the application of encapsulated haem, and other synthetic metalloporphyrins, applied to oxidation reactions.

Methacrolein oxide (MACR-oxide) is a four-carbon, resonance-stabilized Criegee intermediate produced from isoprene ozonolysis, yet its reactivity is not well understood. This study identifies the functionalized hydroperoxide species, 1-hydroperoxy-2-methylallyl formate (HPMAF), generated from the reaction of MACR-oxide with formic acid using multiplexed photoionization mass spectrometry (MPIMS, 298 K = 25 °C, 10 torr = 13.3 hPa). Electronic structure calculations indicate the reaction proceeds via an energetically favorable 1,4-addition mechanism. The formation of HPMAF is observed by the rapid appearance of a fragment ion at m/z 99, consistent with the proposed mechanism and characteristic loss of HO2 upon photoionization of functional hydroperoxides. The identification of HPMAF is confirmed by comparison of the appearance energy of the fragment ion with theoretical predictions of its photoionization threshold. The results are compared to analogous studies on the reaction of formic acid with methyl vinyl ketone oxide (MVK-oxide), the other four-carbon Criegee intermediate in isoprene ozonolysis.

In trivalent chromium plating processes, the breakdown of useful electrolyte components or the formation of hazardous products, in particular Cr(VI), at the anode is obviously undesired. In this study, the oxidation reactions in trivalent chromium electrolytes with formate as complexing agent are investigated at platinum and at a catalytic mixed metal oxide (MMO) coating comprising iridium oxide (IrO2) and tantalum oxide (Ta2O5) using cyclic voltammetry combined with On-Line Electrochemical Mass Spectrometry (OLEMS) measurements.At platinum the following sequence of reaction steps is proposed (all potentials vs. SCE): 1. Oxidative adsorption of [Cr(HCOO)(H2O)5]2+, reversible at −0.4 V; 2. CO2 evolution from the Cr(III)-formate complex above +0.4 V; 3. Further oxidation to HCr O 4 − with simultaneous CO2 and O2 evolution above +1.2 V. Cr(VI) formation also occurs in the absence of formic acid, i.e. when only C r ( H 2 O ) 6 3 + is present in the electrolyte. At a catalytic MMO coating the adsorption step is absent, as well as any subsequent oxidation of the Cr(III)-formate complex. This suggests that adsorption of the Cr(III) complex is required for Cr(VI) formation. MMO electrodes allow a safe usage of the electrolyte for industrial applications, whereas platinum electrodes do not.

Fluorous Biphasic Catalysis (FBC) has been a more than a two decades old concept, that constituted a paradigm shift in bi and triphasic homogeneous catalysis reactions. FBC has expanded over the years to include a variety of conceptually innovative strategies, enabling the quick separation and recovery of suitable precatalysts, from substrates and products. An overview of the development of selective FBC oxidation reactions, including allylic oxidation, peroxidation, epoxidation of alkenes, and oxidation of primary and secondary alcohols to carbonyl compounds, is presented, with the major focus on the authors' contributions to the field, showcasing the principles of fluorous precatalyst design, and the potential of FBC in its many variants. (C) 2018 Elsevier B.V. All rights reserved.

Mesoporous silica nanoparticles (MSNs) are an interesting class of nanomaterials with potential applications in different therapeutic areas and that have been extensively used as drug carriers in different fields of medicine. The present work is focused on the synthesis of MSNs containing a maleamato ligand (MSN-maleamic) and the subsequent coordination of copper(II) ions (MSN-maleamic-Cu) for the exploration of their potential application as antibacterial agents. The Cu-containing nanomaterials have been characterized by different techniques and the preliminary antibacterial effect of the supported maleamato-copper(II) complexes has been tested against two types of bacteria (Gram positive and Gram negative) in different assays to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The biological results showed a moderate antibacterial activity against Escherichia coli which motivated a more detailed study of the antibacterial mechanism of action of the synthesized maleamate-containing nanosystems and whose findings showed oxidative stress generation in bacterial cells. All the prepared nanomaterials were also tested as catalysts in the &ldquo, solvent free&rdquo, selective oxidation of benzyl alcohol, to observe if there is a potential correlation between the catalytic oxidation capacity of the materials and the observed oxidative stress in bacteria. This may help in the future, for a more accurate rational design of antibacterial nanosystems, based on their observed catalytic oxidation activity.

Ajuts: Manel del Valle thanks the support from program ICREA Academia. Nitrite (NO 2− ) oxidation reactions (NOR) have been performed using a pristine glassy carbon (GC) electrode and Pd modified GC electrode to investigate catalysis and kinetics of oxidation reaction. The XPS analysis revealed that Pd nanoparticles (NPs) on GC is differed electronically from Pd particles alone. Electrochemical observations entailed that the Pd-GC electrode improved the catalytic efficiency by lowering peak potential and improving peak current compared to those obtained by GC or Pd electrode alone. Additionally, the onset potential (E i ) of kinetic process concerning NOR was appeared at 0.63 V for Pd-GC electrode which is smaller than 0.81 V and 0.75 V observed by GC and Pd electrodes, respectively. These observations suggest that the Pd-GC electrode can obtain faster electron transfer and maximum catalytic sites. The validation of Pd-GC as noble catalyst is also supported by observing least free energy of activation at peak (ΔG p‡ = 0.461 eV). The nitrite ions involve a single electron transfer reaction with NO 2 molecules being the product, which later undergoes through a dispropornation reaction yielding NO 2− and NO 3− as final products. The precise observations by RDE experiments revealed that the charge transfer reaction followed by an irreversible first order kinetics with standard rate constant (k 0 ) of 1.98 × 10 −4 cm/s and formal potential (E o ' ) of 0.03 V.

Oxides with good catalytic performances and more selectivity to valuable chemicals attract numerous research interests for the oxidation of hydrocarbon fuels. Taking advantage of the nanocasting route, CeFe-based nanocomposites were prepared and characterized to achieve superior stability in the oxidation of cyclic compounds. Adding a third metal (Me = Ni2+, Mn2+/Mn3+ or Co2+/Co3+) to the CeFe-based oxide helped the formation of Ce3+/Ce4+, Fe2+/Fe3+ and active couples in the ternary nanocomposites. The solids having a spherical morphology and good textural properties enabled the formation of promising ternary oxide catalysts for the oxidation of ethylbenzene compared with those of binary and single monoxide nanocomposites. The close contact among the Ce3+/Ce4+ and Fe2+/Fe3+ pairs with Ni2+ species provided the formation of a highly stable CeFeNi catalyst with enhanced performance in the oxidation of cyclic compounds such as ethylbenzene, styrene and benzyl alcohol substrates.

The hexadentate ligand, 2,2′-bis(salicylideneamino)azobenzene, 1 has been synthesized from 2,2′-diaminoazobenzene and salicylaldehyde in refluxing diethyl ether. Reaction of ligand 1 with Cu(II) acetate and Cu(II) perchlorate separately in methanol afforded tetradentate (N,N,N,O) Cu(II) complexes, Cu(L) & [Cu(HL)]ClO4 respectively [where H2L represent the one imine moiety cleavage product of ligand 1 (H represents the dissociable amino and phenolic protons)]. These were characterized by microanalytical data and spectroscopic studies. In addition, the crystal structures of the ligand 1 and complexes Cu(L) & [Cu(HL)]ClO4 were determined by X-ray diffraction analysis. The diffraction analysis revealed that the ligand (H2L) binds Cu(II) centers in (N,N,N,O) tetra dentate fashion in distorted square planer geometry. In complex [Cu(HL)]ClO4 the apical position of copper center is weakly coordinated with one perchlorate ion. The dimeric structure of the molecule [Cu(HL)]ClO4 is stabilized through NH2···O hydrogen bonds. The fluorescence and redox property of ligand 1 and complexes Cu(L) & [Cu(HL)]ClO4 were studied. Preliminary DFT calculations were carried out using crystallographic coordinates to understand the electronic spectra and redox properties of the ligand and complexes. The complex Cu(L) shows very good catalytic activities towards oxidation of benzyl alcohol to benzaldeyhde (under solvent-free condition) and organic thioethers to sulfoxide and sulfones using H2O2 as the oxidant.

International audience; In the last decade organic–inorganic hybrid materials have become essential in materials science as they combine properties of both building blocks. Nowadays the main routes for their synthesis involve electrostatic coupling, covalent grafting, and/or solvent effects. In this field, polyoxometalates (POMs) have emerged as interesting inorganic functional building blocks due to their outstanding properties. In the present work the well‐known α‐Keggin polyoxometalate, α‐PW12O403− (PW), is shown to form hybrid crystalline materials with industrial (neutral) polyethylene glycol oligomers (PEG) under mild conditions, that is, in aqueous medium and at room temperature. The formation of these materials originates from the spontaneous self‐assembly of PW with EOx, (EO=ethylene oxide) with at least four EO units (x>4). The PW–PEG nanoassemblies, made of a POM surrounded by about two PEG oligomers, are stabilized by electrostatic repulsions between the negatively charged PW anions. Addition of NaCl, aimed at screening the inter‐nanoassembly repulsions, induces aggregation and formation of hybrid crystalline materials. Single‐crystal analysis showed a high selectivity of PW towards EO5–EO6 oligomers from PEG200, which is made of a mixture of EO3–8. Therefore, a general “soft” route to produce POM–organic composites is proposed here through the control of electrostatic repulsions between spontaneously formed nanoassemblies in water. However, this rational design of new POM hybrid (crystalline) materials with hydrophilic blocks, using such a simple mixing procedure of the components, requires a deep understanding of the molecular interactions.

This work presents the recovery of biosorption supports as an alternative source of benign production of heterogeneous catalysts for oxidation reactions in mild conditions. Cr-containing FAU zeolite, in sodium form (NaY) and in proton form (HY), was recovered from biosorption studies and reused as support for the preparation of heterogeneous catalysts by the flexible ligand method, using 1,3-diphenyltriazene derivatives. Results showed that the ligand play an important role in the coordination of Cr inside the zeolite. The catalysts showed good activity for the oxidation of cyclohexanol, reaching a maximum of 63.5% conversion. Cr leaching was evaluated and it was found that the Cr–FAU supports lost some of the Cr into the reaction medium, whereas immobilization of Cr-complexes reduced the referred leaching. For the cyclohexene oxidation, a maximum 72.9% conversion was achieved with a HY zeolite-based catalyst., This work was partially funded by the Centre of Biological Engineering and the Centre of Chemistry (University of Minho, Portugal) through FCT strategic projects PEst-OE/EQB/LA0023/2013 and PEst-C/QUI/UI0686/2011 (nF-COMP-01-0124-FEDER-022716), the Project “BioEnv - Biotechnology and Bioengineering for a sustainable world”, REF. NORTE-07-0124-FEDER-000048, co-funded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN and FEDER, and by the Spanish Ministry of Science and Innovation (CTQ2008-04261/PPQ).

Fe(N2Py2)/H 2 O 2 /AcOH catalytic systems provide powerful tools for efficient C-H and C=C bond oxidations (N2Py2 = bis-alkylamine-bis-pyridine ligand). Yet, the stability of these catalysts under the oxidizing conditions still remains a problem. The generally accepted catalyst decomposition pathway of Fe(N2Py2) complexes is through oxidative dimerization to form inactive oxo-bridged Fe 2 (μ-O)(N2Py2) 2 dimers. Detailed ESI-MS analysis has now shown a catalyst decomposition pathway of ligand oxidation via C-H oxidation on the 2-pyridinylmethylene sites, followed by dissociation of the oxidized ligand from the iron center. By deuterating the 2-pyridinylmethylene sites of a series of N2Py2 ligands with variations on both alkylamine and pyridine fragments, providing access to the corresponding Fe(N2Py2-D 4 ) complexes, longer catalysts lifetimes are achieved in catalytic oxidation reactions with all complexes. As a consequence, improved substrate conversions and product yields were consistently observed in both aliphatic C-H oxidations and alkene epoxidations. Kinetic and catalytic studies revealed that deuteration does not change the intrinsic reactivity and product selectivity of Fe(N2Py2) complexes. In addition, different Fe(N2Py2-D 4 ) complexes provide different improvements in catalytic performances and lifetimes, responding to the differences in ligand rigidity and robustness of the corresponding nondeuterated N2Py2 ligands. Accordingly, these improvements are more pronounced for ligands with a more flexible bis-alkylamine backbone. These observations provide insights into the development of more robust ligands for homogeneous oxidation catalysis.

© 2018 The Royal Society of Chemistry. Molecular oxygen is without doubt the greenest oxidant for redox reactions, yet aerobic oxidation is one of the most challenging to perform with good chemoselectivity, particularly on an industrial scale. This collaborative review (between teams of chemists and chemical engineers) describes the current scientific and operational hurdles that prevent the utilisation of aerobic oxidation reactions for the production of speciality chemicals and active pharmaceutical ingredients (APIs). The safety aspects of these reactions are discussed, followed by an overview of (continuous flow) reactors suitable for aerobic oxidation reactions that can be applied on scale. Some examples of how these reactions are currently performed in the industrial laboratory (in batch and in flow) are presented, with particular focus on the scale-up strategy. Last but not least, further challenges and future perspectives are presented in the concluding remarks. crosscheck: This document is CrossCheck deposited identifier: Simon Kuhn (ORCID) copyright_licence: The Royal Society of Chemistry has an exclusive publication licence for this journal copyright_licence: This article is freely available. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (CC BY 3.0) history: Received 30 August 2016; Accepted 13 September 2016; Advance Article published 22 September 2016; Version of Record published 22 November 2016 ispartof: Reaction Chemistry & Engineering vol:1 issue:6 pages:595-612 status: published

In recent years, several research groups have focused their attention on the development of synthetic and functional models of biological systems based on copper. Here we report the synthesis strategy, characterization, and catalytic activity for new copper-based porphyrins (CuP2 and CuP3) isolated by metallation of the corresponding free base derivatives, H2P2 and H2P3. The solid CuP2S was obtained from the reaction of H2P2 with copper(II) acetate (10 equiv.). These complexes have been used in homogeneous (CuP2 and CuP3) and heterogeneous (CuP2S) oxidative catalysis of 3,5-di-tert-butylcatechol and catechol, in the presence of air, with or without hydrogen peroxide. The obtained results show that the new copper porphyrins CuP2 and CuP3 and the CuP2S material are able to efficiently mimic the activity of catechol oxidase, the latter being easily reused and maintaining its activity for more than three catalytic cycles.

Wastewater pollution with heavy metals is an issue of great environmental concern. The future development of clean technologies for the treatment of wastewater loaded with heavy metals entails environment friendly and sustainable processes that may allow simultaneously the recovery of the metals and their reutilization as value-added catalysts to be used in environmental applications. This is the first review regarding the biorecovery of metals and their further reutilization as heterogeneous catalysts. In this regard, metallic residues that generally would be considered as a waste at the end of the treatment process can be reutilized and transformed into value-added catalysts to be used in environmental applications. This review is focused in two broad areas: the biorecovery of chromium by a combined biosorption system consisting of bacteria supported on zeolites, and the catalytic reutilization of the metal-loaded zeolites in the oxidation of organic compounds, both in gaseous and liquid phase. After an overview describing the main subjects in the field of heavy metals recovery, biosorption, zeolites and catalytic oxidation, in the following sections special emphasis will be given to the main results and findings regarding these clean technologies of biorecovery and reuse of metals in catalytic reactions of environmental concern., B. Silva is thankful for the Project “BioEnv—Biotechnology and Bioengineering for a sustainable world,” REF. NORTE-07-0124-FEDER-000048, cofunded by the Programa Operacional Regional do Norte (ON.2 – O Novo Norte), QREN, FEDER. The authors are grateful to FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the Research Centres, PEst-OE/EQB/LA0023/2013, and PEst-C/QUI/UI0686/2013 (F-COMP-01-0124-FEDER-037302).

In this comprehensive review, the main aspects of using Au/CeO2 catalysts in oxidation reactions are considered. The influence of the preparation methods and synthetic parameters, as well as the characteristics of the ceria support (presence of doping cations, oxygen vacancies concentration, surface area, redox properties, etc.) in the dispersion and chemical state of gold are revised. The proposed review provides a detailed analysis of the literature data concerning the state of the art and the applications of gold–ceria systems in oxidation reactions

Biosorption, the ability of certain materials of biologic origin to entrap metal ions, is a natural process that may be seen as xenobiotic or may be used through technological processes to recover or remediate contaminated ecosystems. This process is known to be very appropriate to remediate liquid effluents with low metal ions concentrations. In the last four or five decades, very interesting publications have been presenting useful applications of biosorption systems aiming the sustainability of some industrial processes, known for sending into the environment huge amounts of heavy metals, contaminating soils, water, air, flora and fauna. Relevant research work has been done using different biosorbents and optimizing operation procedures. Several industrial processes are patented and working effectively for quite a long time. Many good and exhaustive reviews, covering all possible adsorbents, adsorbates and operational parameters, are easily accessible and even this year a couple of them have been presented to the scientific community. In this chapter devoted to biosorption, the applications of biosorption are presented with a new perspective: an integrated system, associating metal entrapment, biological chemical reduction, ion exchange and environmental oxidation catalysis in liquid and in gas phase. The metal residues of some industries are now converted into high value catalysts to be used in mild oxidation of volatile organic compounds, reusing expensive and contaminating metals in the whole industrial activity. Biosorption allows the retention of the metallic ions present in liquid solutions and special attention is paid to hexavalent chromium as it is usually present in the anionic status, making uninteresting for ion-exchange in zeolites, the biomass supports herein presented. The biomass selected for performing biosorption is also able to reduce hexavalent chromium to its trivalent form, which is cationic. Now, the ion exchange within the zeolites is feasible, and the new matrices with the entrapped ions may be used downstream in environmental catalysis. In fact, these so prepared catalysts proved to be more selective towards the degradation of volatiles into C02 than the expensive palladium catalysts. Cr catalysts may be used, as they are, in gaseous phase reactions or may be subject to a pre-treatment with ligants to fix the metal ions inside the zeolitic structure, avoiding the eventual leaching in liquid phase reactions. This chapter aims, in resume, to enlarge the applications of biosorption in an integrated and sustainable procedure, indicating new ways of using microorganisms able to sorb as well as to change the chemical nature of metal ions, of using cationic ion-exchangers to retain original negative ions and of raising the market value of industrial residues by substitution of very expensive environmental catalysts. © 2012 Scrivener Publishing LLC. All rights reserved., (undefined), info:eu-repo/semantics/publishedVersion

Oxidoreductases are promising catalysts for organic synthesis. To sustain their catalytic cycles they require efficient supply with redox equivalents. Today classical biomimetic approaches utilizing natural electron supply chains prevail but artificial regeneration approaches bear the promise of simpler and more robust reaction schemes. Utilizing visible light can accelerate such artificial electron transport chains and even enable thermodynamically unfeasible reactions such as the use of water as reductant. This contribution critically summarizes the current state of the art in photoredoxbiocatalysis (i.e. light-driven biocatalytic oxidation and reduction reactions).

The aminoxyl radical 6-trifluoromethyl-benzotriazol-N-oxyl (TFNO) has been generated from the parent hydroxylamine 6-CF3-1-hydroxy-benzotriazole (TFBT) by one-electron oxidation with a CeIV salt and characterized by spectrophotometry and cyclic voltammetry (CV). Rate constants of H-abstraction (kH) by TFNO from a number of H-donor benzylic substrates have been determined spectrophotometrically in MeCN solution at 25 °C. A radical H-atom transfer (HAT) route of oxidation is substantiated for TFNO by several pieces of evidence. The kinetic data also testify the relevance of stereoelectronic effects upon the HAT reactivity of TFNO. Copyright © 2010 John Wiley & Sons, Ltd.

International audience; We synthesized new cyanoaromatics, benzo[b]triphenylene-9,14-dicarbonitrile (DBTP) 1a and a graftable derivative, 9,14-dicyanobenzo[b]triphenylene-3- carboxylic acid (DBTP-COOH) 1b, easily prepared from commercial reagents. Their photosensitizing properties were investigated. Hybrid porous silica monoliths loaded with encapsulated 1a or grafted 1b were prepared, and their adsorption, spectroscopic and photosensitizing properties, as well as stability, were compared. Solvent-free, efficient oxidation of dimethylsulfide (DMS) was observed at the gas-solid interface under visible light irradiation. Quantum yields of formation of 1O2 inside the porous monoliths are comparable to those of phenalenone. Singlet oxygen lifetimes (∼25 μs) were found to be longer in silica monoliths than in usual polar solvents such as methanol or ethanol. This new class of hybrid materials work as porous, transparent, and highly efficient microreactors for oxidation reactions under visible light.