DFT study of dihydrogen addition to molybdenum π-heteroaromatic complexes: a prerequisite step for the catalytic hydrodenitrogenation process

International audienceThe range of molybdenum hydride complexes that are sought to participate in the important catalytic hydrodenitrogenation process (HDN) of nitrogen containing polycyclic aromatic hydrocarbons were evaluated by DFT studies. The previously synthesized stable (η6-quinoline)Mo(PMe3)3 complex 1N, in which molybdenum is bonded to the heterocyclic ring, was chosen as a model. The hydrogenation of the quinone heterocycle, which was postulated as the initial step in the overall HDN reaction, is found to occur via three consecutive steps of the oxidative addition of dihydrogen to Mo in 1N. Successive transfer of hydrogen atoms from the metal to the heterocycle leads to the ultimate formation of the tetrahydrido molybdenum intermediate Mo(PMe3)4H413 and 2,2,3,3-tetrahydroquinoline C9H11N 14. All the involved intermediates and transition states have been fully characterized by DFT. This computational modeling of the hydrogenation of quinoline, as a part of extended HDN catalytic processes, provides a fundamental understanding of such mechanism

Theoretical studies of mixed-valence organometallic species for potential utilization as quantum cellular automata

International audienceThe chemistry of mixed-valence complexes joins that of molecular electronics in the quantum cellular automata (QCA) paradigm, a concept which has been demonstrated to be a possible alternative to the transistor-based technology, in which binary information is encoded in the configuration of charge among redox-active molecular sites. Experimental and theoretical efforts have recently been devoted to molecular mixed-valence organometallic systems containing two and four metal centers as candidates for QCA. Properties of specific examples based on hypothetical organometallic molecules are theoretically analyzed and discussed with the aid of DFT calculations

Electronic, geometrical, and thermochemical studies on group-14 element-diruthenaborane cluster compounds: a theoretical investigation

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Reactions of nickelocene with an Ru(5) cluster: crystal structures of two nickel-ruthenium clusters containing C(2) ligands

Reactions of nickelocene with Ru5(μ₅-C₂)(μ-SMe)₂(μ-PPh₂)₂(CO)₁₁ have given NiRu₅(μ₆-C₂)(μ-SMe)₂(μ-PPh2)₂- (CO)₉Cp₂ and Ni₂Ru4(μ₆-C₂)(μ-SMe)₂(μ-PPh₂)₂(CO) ₈Cp₂ whose molecular structures have been determined. The NiRu5 cluster is related to other heterometallic clusters containing FeRu₅, Ru₆ or Co₂Ru₅ cores which contain two edge-fused squares supporting the C₂ ligand, one carbon occupying the centre of each square face while retaining the C–C bond. However, there is no formal M–M interaction along the shared edge. Substitution of CO groups by Cp on one Ru atom has occurred. The structure of the Ni₂Ru₄ cluster is similar, with the six-membered ring having the boat conformation. The C₂ ligand takes up two disordered (1 : 1) positions, either parallel or perpendicular to the non-bonding Ni _ _ _ Ni vector. Extended Hückel and density functional calculations have been carried out on Ni₂Ru₄(μ₆-C₂)(μ-SMe)₂(μ-PPh₂)₂ (CO)₈Cp₂ to rationalise these two observed coordination modes of the C₂ unit to the metal framework. Results suggest that the two arrangements are isoenergetic and that the M–C bonding follows the Dewar–Chatt–Duncanson model as previously found for related C₂-containing polynuclear organometallic clusters.Chris J. Adams, Michael I. Bruce, Jean-François Halet, Samia Kahlal, Brian W. Skelton and Allan H. Whit

Small Ligated Organometallic Pd n Clusters (n= 4 - 12): A DFT Investigation

International audienceDFT calculations were carried out at the BP86/LANL2DZ level of theory to probe the structures and relative stabilities of small and medium size ligated palladium clusters. Results show that optimized geometries satisfactorily mimic experimental structural data. Observed cluster electron counts generally deviate from the expected Wade–Mingos electron counts because of the presence of several non-conical T-shaped ML 3 fragments in the clusters. These species are thermodynamically stable with substantial HOMO–LUMO gaps. © 2017, Springer Science+Business Media New York

Thermally induced inter-ring haptotropic rearrangements in π-complexes of molybdenum with nitrogen containing polyaromatic heterocycles: A DFT study

International audienceInter-ring haptotropic rearrangements (IRHRs) are well-known phenomena in fluxional ogranometallic chemistry. They are mainly observed for transition metal complexes with polyaromatic ligands (PALs), but are usually limited to PALs without heteroatoms. Here, we report DFT studies of recent experimentally observed IRHRs in heterocyclic complexes of Mo. Four different ligands (quinoline, isoquinoline, quinoxaline, and indolyl) have been investigated. Overall, structural and energetic trends agree well with available experimental data. In addition, mechanistic trends and heteroatom participation are discussed and elucidated to further understanding of IRHRs in heterocyclic polyaromatic complexes in particular, and haptotropic processes in genera

[Ag7(H){E2P(OR)2}6] (E = Se, S): Precursors for the Fabrication of Silver Nanoparticles

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Synthèse d'analogues d'inhibiteurs d'histone désacétylases

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