Theoretical investigation of triple bond in molybdenum complexes trans-[X(PMe3)4MoE(Mes)] (X=F, Cl, Br, I; E=Si, Ge, Sn, Pb): A DFT study
2012; Elsevier BV; Volume: 37; Issue: 1 Linguagem: Inglês
10.1016/j.poly.2012.02.020
ISSN1873-3719
AutoresKrishna K. Pandey, Pankaj Patidar,
Tópico(s)Organometallic Complex Synthesis and Catalysis
ResumoQuantum-chemical calculations were used to investigate the molecular and electronic structures as well as bonding energies of the molybdenum–ylidyne complexes trans-[X(PMe3)4MoE(Mes)] (X = F, Cl, Br, I; E = Si, Ge, Sn, Pb) at the BP86/TZ2P/ZORA level of theory. The calculated geometrical results are in excellent agreement with the available experimental results. The MoE bond distances are significantly short, and the calculated Pauling Mo–E bond orders are ∼2.40–2.65. The electronic structures of the MoE bonds show the presence of genuine triple bond containing an σ-bond and two π-bonds in all studied complexes. The MoE σ-bonds are polarized towards the heavier group 14 elements while the π-bonds are polarized towards the molybdenum metal. The partial charges on the [EMes]+ fragments (0.67–0.93) indicate that the overall charges flow from the metal fragments to the [EMes]+ fragments. The nature of MoE bonds also investigated by means of energy decomposition analysis which reveals that the metal–ligand π-orbital interactions between [X(PMe3)4Mo]− and [EMes]+ fragments are the most dominant interactions, contributing (80–85%) to the total ΔEorb terms. The strength of MoE bonds mainly depends on the π-acceptor ability of [EMes]+ group. It decreases when 14 group element becomes heavier in the trend Si > Ge > Sn > Pb and in the order F > Cl > Br > I.
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