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1. In-Depth Theoretical Investigations of Borazine’s Aromaticity: Tailoring Electron Delocalization through Substituent Effects

Author

Alex-Cristian Tomut, Ionut-Tudor Moraru, and Gabriela Nemes

Subjects
“inorganic” benzene, aromaticity, DFT methods, aromaticity indices, NBO analyses, hyperconjugations, Organic chemistry, QD241-441
Abstract

The current study investigates the influence of several R substituents (e.g., Me, SiH3, F, Cl, Br, OH, NH2, etc.) on the aromaticity of borazine, also known as the “inorganic benzene”. By performing hybrid DFT methods, blended with several computational techniques, e.g., Natural Bond Orbital (NBO), Quantum Theory of Atoms in Molecules (QTAIM), Gauge-Including Magnetically Induced Current (GIMIC), Nucleus-Independent Chemical Shift (NICS), and following a simultaneous evaluation of four different aromaticity indices (para-delocalization index (PDI), multi-centre bond order (MCBO), ring current strength (RCS), and NICS parameters), it is emphasized that the aromatic character of B-substituted (B3R3N3H3) and N-substituted (B3H3N3R3) borazine derivatives can be tailored by modulating the electronic effects of R groups. It is also highlighted that the position of R substituents on the ring structure is crucial in tuning the aromaticity. Systematic comparisons of calculated aromaticity index values (i.e., via regression analyses and correlation matrices) ensure that the reported trends in aromaticity variation are accurately described, while the influence of different R groups on electron delocalization and related aromaticity phenomena is quantitatively assessed based on NBO analyses. The most relevant interactions impacting the aromatic character of investigated systems are (i) the electron conjugations occurring between the p lone pair electrons (LP) on the F, Cl, Br, O or N atoms, of R groups, and the π*(B=N) orbitals on the borazine ring (i.e., LP(R)→π*(B=N) donations), and (ii) the steric-exchange (Pauli) interactions between the same LP and the π(B=N) bonds (i.e., LP(R)↔π(B=N) repulsions), while inductive/field effects influence the aromaticity of the investigated trisubstituted borazine systems to a much lesser extent. This work highlights that although the aromatic character of borazine can be enhanced by grafting electron-donor substituents (F, OH, NH2, O−, NH−) on the N atoms, the stabilization due to aromaticity has only a moderate impact on these systems. By replacing the H substituents on the B atoms with similar R groups, the aromatic character of borazine is decreased due to strong exocyclic LP(R)→π*(B=N) donations affecting the delocalization of π-electrons on the borazine ring.

Published
2024
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2. New Quinazolin-4(3H)-One Derivatives Incorporating Isoxazole Moiety as Antioxidant Agents: Synthesis, Structural Characterization, and Theoretical DFT Mechanistic Study

Author

Yassine Rhazi, Riham Sghyar, Noemi Deak, Bouchra Es-Sounni, Bouchra Rossafi, Albert Soran, Mustapha Laghmari, Azize Arzine, Asmae Nakkabi, Khalil Hammani, Samir Chtita, Mohammed M. Alanazi, Gabriela Nemes, and Mohamed El. Yazidi

Subjects
quinazolin-(3H)-one, isoxazole, DFT mechanistic study, antioxidant agents, Medicine, Pharmacy and materia medica, RS1-441
Abstract

Background: This research centers on the development and spectroscopic characterization of new quinazolin-4(3H)-one-isoxazole derivatives (5a–e). The aim was to investigate the regioselectivity of the 1,3-dipolar cycloaddition involving arylnitriloxides and N-propargylquinazolin-4(3H)-one, and to assess the antioxidant properties of the synthesized compounds. The synthetic approach started with the alkylation of quinazolin-4(3H)-one using propargyl bromide, followed by a 1,3-dipolar cycloaddition reaction. Methods: The structural identification of the products was performed using various spectroscopic methods, such as IR, 1H, 13C, and HMBC NMR, HRMS, and single-crystal X-ray diffraction. To further examine the regioselectivity of the cycloaddition, Density Functional Theory (DFT) calculations at the B3LYP/6-31G(d) level were employed. Additionally, the antioxidant potential of the compounds was tested in vitro using DPPH (2,2-Diphenyl-1-picrylhydrazyl)radical scavenging assays. The reaction selectively produced 3,5-disubstituted isoxazoles, with the regiochemical outcome being independent of the substituents on the phenyl ring. Results: Theoretical calculations using DFT were in agreement with the experimental results, revealing activation energies of −81.15 kcal/mol for P-1 and −77.32 kcal/mol for P-2, favoring the formation of P-1. An analysis of the Intrinsic Reaction Coordinate (IRC) confirmed that the reaction proceeded via a concerted but asynchronous mechanism. The antioxidant tests demonstrated that the synthesized compounds exhibited significant radical scavenging activity, as shown in the DPPH assay. The 1,3-dipolar cycloaddition of arylnitriloxides with N-propargylquinazolin-4(3H)-one successfully resulted in novel 3,5-disubstituted isoxazoles. Conclusions: The experimental findings were well-supported by theoretical predictions, and the antioxidant assays revealed strong activity, indicating the potential for future biological applications of these compounds.

Published
2024
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6. Theoretical Insights into the Structural Differences between Organic and Inorganic Amines/Ethers

Author

Florin Teleanu, Ionut-Tudor Moraru, and Gabriela Nemes

Subjects
Computational chemistry, Chemistry, Physical and Theoretical Chemistry
Abstract

The contrasting geometrical features between organic and inorganic counterparts of amines and oxanes are explained in terms of an offset between attractive (donor-acceptor) and repulsive (donor-donor) interactions. Natural bond orbital (NBO) calculations carried out at the density functional theory level of theory reveal that hyperconjugative effects in the organic amines and ethers are overcome by repulsive interactions occurring between the lone pair on the nitrogen/oxygen atom and the adjacent σ(C-R) bond orbitals. Although displaying lower energies than in the corresponding organic derivatives, the LP(X) → σ*(E-R) (X = N, O; E = Si, Ge, Sn) interactions in heavier counterparts overcome the LP(X)···σ(E-R) repulsions, impacting thus their structural behavior. In addition, NBO deletion optimizations emphasize that among hyperconjugations, back-bonding effects of the LP(X) → d(E) type dictate to a lesser extent the anomalous structures of the inorganic amines and oxanes.

Published
2020

7. Palladium and Ruthenium Derivatives Stabilised by bis-Sulfone Ligand

Author

Sonia Mallet-Ladeira, Raluca Septelean, Gabriela Nemes, Noémi Deak, Ionut-Tudor Moraru, David Madec, Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University [Cluj-Napoca] (UBB), Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), and Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010405 organic chemistry, Chemistry, Ligand, chemistry.chemical_element, General Chemistry, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Sulfone, Ruthenium, chemistry.chemical_compound, Polymer chemistry, [CHIM]Chemical Sciences, [CHIM.COOR]Chemical Sciences/Coordination chemistry, ComputingMilieux_MISCELLANEOUS, Palladium
Abstract

International audience

Published
2018
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8. The Role of Monoanionic Aryl Pincer Ligands in the Stabilization of Group 14 Metallylenes

Author

Gabriela Nemes, Noémi Deak, David Madec, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Universitatea Babeş-Bolyai [Cluj-Napoca], Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Carbon group, 010405 organic chemistry, Ligand, Stereochemistry, Chemistry, Aryl, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Pincer movement, Inorganic Chemistry, chemistry.chemical_compound, Group (periodic table), Reactivity (chemistry), [CHIM.COOR]Chemical Sciences/Coordination chemistry
Abstract

International audience; Pincer ligands have an important role in stabilizing group 14 metallylenes. The particular structure of the aryl pin-6 cer ligands makes them a unique ligand platform. This review is focused on presenting monoanionic metallylenes stabilized by aryl pincer-type ligands, described so far in the literature, with focus on their synthesis, structural features, and reactivity.Throughout this work, the close correlation between structure11and reactivity is highlighted, as well as the manner in which thisinfluences the stability of the compounds and their potentialapplications.

Published
2020
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9. New phosphorus containing bis-sulfone ligands

Author

David Madec, Noémi Deak, Luminita Silaghi-Dumitrescu, Gabriela Nemes, Sonia Mallet-Ladeira, Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Phosphorus containing, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Sulfone, chemistry.chemical_compound, chemistry, [CHIM]Chemical Sciences, [CHIM.COOR]Chemical Sciences/Coordination chemistry, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017
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10. Bridging a Knowledge Gap from Siloxanes to Germoxanes and Stannoxanes. A Theoretical Natural Bond Orbital Study

Author

Petronela M. Petrar, Gabriela Nemes, and Ionuţ-Tudor Moraru

Subjects
chemistry.chemical_compound, Bridging (networking), chemistry, Chemical bond, 010405 organic chemistry, Computational chemistry, Siloxane, Physical and Theoretical Chemistry, 010402 general chemistry, Equilibrium geometry, 01 natural sciences, 0104 chemical sciences, Natural bond orbital
Abstract

Explaining the nature of the E-O chemical bond (E = Si, Ge, Sn) has been a great challenge for theoretical chemists during the last decades. Among the large number of models used for this purpose, the one based on hyperconjugative interactions sheds more light on the nature of chemical bonding in siloxanes. Starting from this concept, this study aimed to evaluate the impact of siloxane type hyperconjugative effects on the structural features of germoxanic and stannoxanic species and in addition to assess if p-d-like back-bonding interactions can also play important roles in determining the particular structures of these heavier analogues of ethers. Natural bond orbital deletion (NBO DEL) optimizations, carried out at the DFT level of theory, revealed that hyperconjugative effects dictate to a large extent the structural behavior of these species. Furthermore, this study points out that p-d back-bonding interactions also influence the equilibrium geometry of these species, although acting as a secondary electronic effect within the E-O-E moieties (E = Si, Ge, Sn).

Published
2017

11. Functionalized oxathiacrown macrocycles: Synthesis, characterization and coordination to palladium(II), ruthenium(II) and copper(I)

Author

Ghassoub Rima, Annie Castel, Nathalie Saffon, David Madec, Alina Saponar, Gabriela Nemes, and Guillaume Carel

Subjects
chemistry.chemical_classification, Double bond, Coordination polymer, Organic Chemistry, chemistry.chemical_element, Polymer, Photochemistry, Biochemistry, Copper, Ruthenium, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Transition metal, Polymer chemistry, Materials Chemistry, Macrocyclic ligand, Physical and Theoretical Chemistry, Palladium
Abstract

New oxathiacrown macrocycles with exocyclic double bond 1 and 2 were synthesized and characterized. Their coordination behavior with soft transition metals is investigated. Reaction of 1 with PdCl2 afforded exo-coordinated complex 3 with the two S-donor atoms. With RuCl2(PPh3)3, the macrocyclic ligand 1 is bonded through three donor atoms (two sulfur and one oxygen) to the ruthenium center in a facial coordination mode. By contrast, double and single-stranded one dimensional (1D) coordination polymers were obtained by reaction of CuBr with macrocycles 1 and 2. All complexes were spectroscopically characterized and their structure was secured by X-ray diffraction analysis.

Published
2014
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12. Comparison of reactivity of phosphagermaallene Tip(t-Bu)GeCPMes* towards sulfur ylides

Author

Annie Castel, Noémi Deak, Dumitru Ghereg, Jean Escudié, Heinz Gornitzka, Sonia Ladeira, Tibor-Gabor Kocsor, Gabriela Nemes, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Universitatea Babeş-Bolyai [Cluj-Napoca], Laboratoire de chimie de coordination (LCC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées, Institut de Chimie de Toulouse (ICT-FR 2599), and Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)

Subjects
chemistry.chemical_classification, Double bond, Chemistry, Organic Chemistry, Nuclear magnetic resonance spectroscopy, Photochemistry, Biochemistry, Medicinal chemistry, Cycloaddition, Adduct, Inorganic Chemistry, Nucleophile, Ylide, Materials Chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Reactivity (chemistry), Physical and Theoretical Chemistry, Single crystal
Abstract

International audience; Phosphagermaallene 1, Tip(t-Bu)GeCPMes* (Tip = 2,4,6-triisopropylphenyl, Mes* = 2,4,6-tri-tert-butylphenyl), reacts with diphenylsulfoniumylide (Ph2SCH2) leading to adduct 2, through a nucleophilic attack of the negatively charged carbon atom of the ylide on the positively charged germanium atom followed by a migration of one of the phenyl groups. By contrast, dimethyloxosulfoniummethylide (Me2S(O)CH2) appears much less reactive towards 1: it preferentially undergoes an in-situ oxidation of THF leading to a γ-butyrolactone intermediate which gives a [2+2] cycloaddition by the CO group with the GeC double bond to form 3. The new compounds 2 and 3 were completely characterized by multinuclear NMR spectroscopy and by single crystal X-ray structural analysis.

Published
2014
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13. In silico quest for stable phosphastannaallenes

Author

Agota Bartok, Petronela M. Petrar, Jean Escudié, Gabriela Nemes, and Luminita Silaghi-Dumitrescu

Subjects
Crystallography, chemistry.chemical_compound, Stereochemistry, Chemistry, General Chemical Engineering, Electronic effect, Substituent, General Chemistry, Multiple bonds, Bond order
Abstract

A computational study at different levels of theory was performed for the not yet synthesized phosphastannaallenes >Sn C P– in order to evaluate the strength of the Sn C bond, the main postulated factor to stabilize such species, and the geometry in R 2 Sn C PR derivatives. The influence of the substituents with various electronic effects (H, Me, Ph, F, Cl, OMe, SiMe 3 ) at the Sn or P atoms of the Sn C P unit on the Sn C bond order was evaluated in the quest for a substituent that would stabilize the phosphastannaallenic unit. P C bond orders have also been calculated.

Published
2013
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14. Phosphasilaallenes >Si=C=P− and phosphagermaallenes >Ge=C=P−

Author

Gabriela Nemes and Jean Escudié

Subjects
chemistry.chemical_classification, Steric effects, Ketone, Double bond, Chemistry, Stereochemistry, General Chemical Engineering, General Chemistry, Aldehyde, Cycloaddition, Crystallography, Chalcogen, Main group element, Alkyl
Abstract

Phosphasilaallene Tip(Ph)Si = C = PMes* (Tip = 2,4,6-triisopropylphenyl, Mes* = 2,4,6-tri-tert-butylphenyl) and phosphagermaallene Mes2Ge = C = PMes* (Mes = 2,4,6-trimethylphenyl) have been obtained by dehalogenation of their corresponding dihalophosphametallapropenes > E(X)-C(X′) = P− by tert-butyllithium. They dimerize above −40 °C by a cycloaddition involving two E = C double bonds or the E = C and the P = C double bonds but can be characterized at low temperature by trapping reactions and by low field shifts in 31P, 29Si and particularly 13C NMR for the sp carbon atom. Owing to a small increase in the steric hindrance, phosphagermaallene Tip(t-Bu)Ge = C = PMes* can be stabilized and isolated. The Ge = C double bond undergoes nearly quantitative [2 + 1] cycloadditions with chalcogens and [2 + 2] cycloadditions with aldehydes or ketones. The surprisingly stable lithiochlorosilane R(Cl2)Si-C(Li) = PMes* (R = 9-methylfluorenyl) behaves as a synthetic equivalent of the phosphasilaallene R(Cl)Si = C = PMes*. With two alkyl groups (t-Bu) on the germanium atom, the phosphagermaallene t-Bu2Ge = C = PMes* is not obtained but its formal dimers 1,3-digermacyclobutanes have been isolated.

Published
2010
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15. An insight into the structure of model germaphosphaallenes

Author

Henri Ranaivonjatovo, Petronela M. Petrar, Ioan Silaghi-Dumitrescu, Jean Escudié, Gabriela Nemes, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Babes bolyai, UNIVERSITE KOGALNICEANU, Department of Chemistry, Babes-Bolyai University [Cluj-Napoca] (UBB), Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Electron density, [CHIM.ORGA]Chemical Sciences/Organic chemistry, 010405 organic chemistry, Chemistry, Biophysics, 010402 general chemistry, Condensed Matter Physics, Antibonding molecular orbital, 01 natural sciences, 0104 chemical sciences, Crystallography, Computational chemistry, Phosphorus atom, Physical Sciences, Electronic effect, Physical and Theoretical Chemistry, Molecular Biology, Lone pair, ComputingMilieux_MISCELLANEOUS, Natural bond orbital
Abstract

The geometries of all possible isomers of the model compound H2Ge=C=PH were optimized at the B3LYP/6-31G(d,p) level of the theory. The calculation were repeated at higher correlated methods with similar results and for the the isomers of the methyl-substituted phosphagermaallene MeP=C=GeMe2. As another way to stabilise the P=C=Ge unit consists in the use electronic effects, a NBO study was carried out in order to identify the influence that the nature (electropositive or electronegative) of several substituents would have on the strength of the C=Ge bond. Model compounds HP=C=GeR2 and HP=C=GeRR′ were investigated (R = BH2, CH3, SiH3, NH2, OMe, F; R′ = H). It was found that the main interaction contributing to the weakening of the C=Ge bond is a transfer of electron density from the lone pair of the phosphorus atom to the molecular antibonding orbital localized on the Ge–C bond.

Published
2009
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16. The first evidence for a transient stibaallene ArSbCCR2

Author

Henri Ranaivonjatovo, Ioan Silaghi-Dumitrescu, Luminita Silaghi-Dumitrescu, Lise Baiget, Gabriela Nemes, and Jean Escudié

Subjects
chemistry.chemical_classification, Double bond, Organic Chemistry, Ab initio, Biochemistry, Fluorenylidene, Inorganic Chemistry, Crystallography, chemistry, Computational chemistry, Materials Chemistry, Butyllithium, Molecular orbital, Transient (oscillation), Physical and Theoretical Chemistry
Abstract

Dechlorofluorination of ArSb(F)–C(Cl) CR 2 (CR 2 = fluorenylidene, Ar = 2,4,6-tri- tert -butylphenyl) by tert -butyllithium afforded a 3,4-bis(fluorenylidene)-1,2-distibacyclobutane. The formation of the latter probably involves the transient stibaallene ArSb C CR 2 followed by a head-to-head dimerization via two Sb C double bonds. Molecular orbital calculations at the ab initio and DFT levels support the head-to-head dimerization of ArSb C CR 2 with the formation of a 1,2-distibacyclobutane.

Published
2005
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17. Novel stable phosphastannapropene derivatives. Synthesis and characterization

Author

Raluca Septelean, Gabriela Nemes, Heinz Gornitzka, Noémi Deak, Petronela M. Petrar, Babes-Bolyai University [Cluj-Napoca] (UBB), Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Babes bolyai, and UNIVERSITE KOGALNICEANU

Subjects
010405 organic chemistry, Stereochemistry, Organic Chemistry, chemistry.chemical_element, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, 01 natural sciences, Biochemistry, Medicinal chemistry, 0104 chemical sciences, Characterization (materials science), Inorganic Chemistry, chemistry, Atom, Materials Chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry, Tin
Abstract

International audience; Phosphastannapropenes containing the -P=C-Sn < moiety are very scarcely reported in the literature, but their structure suggests that they can be of interest as precursors of inorganic materials, and their potential catalitic activity is worth investigating. Several new phosphastannapropenes were synthesized starting from the dichlorophosphaalkene Mes*P=CCl2 (Mes* = 2,4,6-tri-tertbutyl-phenyl) and dichlorotin derivatives following the synthetic route similar to that described in the literature for phosphasilaand phosphagermapropenes. The tin atom is either substituted by organic groups with low sterical hindrance, or incorporated in a cyclic system. The compounds were characterized by multinuclear NMR spectroscopy and, in some cases, single-crystal X-ray diffraction.

Published
2015
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18. New silyl-substituted phosphaalkenes Mes*PC(Cl)–Si(Cl)PhR, promising building blocks in silicon and phosphorus chemistry

Author

Sonia Mallet-Ladeira, Henri Ranaivonjatovo, Luminita Silaghi-Dumitrescu, Petronela M. Petrar, Agota Bartok, Heinz Gornitzka, Nathalie Saffon, Gabriela Nemes, Catherine Hemmert, Raluca Septelean, Universitatea Babeş-Bolyai [Cluj-Napoca], Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Laboratoire de chimie de coordination (LCC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), and Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Silylation, Silicon, Inorganic chemistry, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Biochemistry, Coordination complex, Low coordinate phosphorus compounds, Inorganic Chemistry, Transition metal, Polymer chemistry, Materials Chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry, Multiple bonding, chemistry.chemical_classification, 010405 organic chemistry, Phosphorus, Organic Chemistry, Phosphasilapropenes, Multiple bonds, 3. Good health, 0104 chemical sciences, chemistry, Gold complexes
Abstract

Three new silyl-substituted phosphaalkenes Mes*P C(Cl)–Si(Cl)PhR (R = chlorine, 1 ; R = 9-methylfluoren-9-yl, 2 ; R = 9-trimethylsilylfluoren-9-yl, 3 ) were obtained and completely characterized. The coordination compounds 4 and 5 , resulting from the reaction between Au(SMe 2 )Cl and 1 and 3 , respectively, are also described. All these compounds are potential precursors of phosphasilaallenes, not stabilized until now and new ligands in transition metal chemistry.

Published
2013
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