Cl₃V(μ-S(CH₃)₂)₃VCl₃^2-:  A First-Row, Face-Shared Bioctahedral Complex with Multiple Metal−Metal Bonding

Abstract

Density functional theory calculations have been used to investigate the structure and bonding of the d(3)d(3) bioctahedral complexes X(3)V(mu-S(CH(3))(2))(3)VX(3)(2)(-) (X = F(-), Cl(-), OH(-), SH(-), NH(2)(-)). According to geometry optimizations using the broken-symmetry approach and the VWN+B-LYP combination of density functionals, the halide-terminated complexes have a V-V bond order of approximately 2, while complexes featuring OH(-), SH(-), or NH(2)(-) as terminal ligands exhibit full triple bonding between the vanadium atoms. The tendency toward triple bonding in the latter complexes is consistent with an increased covalency of the vanadium-ligand bonds, and the influence of bond covalency is apparent also in the tendency for V-V bond elongation in the complexes with OH(-) and NH(2)(-) terminal ligands. Detailed examination of the composition of molecular orbitals in all of the thioether-bridged V(II) complexes substantiates the conclusion that the strong antiferromagnetic coupling which we have determined for these complexes (-J > 250 cm(-)(1)) is due to direct bonding between metal atoms rather than superexchange through the bridging ligands. As such, these V(II) complexes comprise the first apparent examples of multiple metal-metal bonding in first-transition-row, face-shared dinuclear complexes and are therefore of considerable structural and synthetic interest.

Electronic structure and metal–metal bonding in nominal d3d3MIIMIVCl93−(MII = V, Nb, Ta; MIV = Mn, Tc, Re) face-shared binuclear complexes

“…The tendencies evident in our earlier comparison of mixedgroup dimers (viz., the V/Cr and Cr/Mn triad combinations) 17, 18 with their same-group counterparts (i.e., the dimers of the V, 42 Cr, 30,38,40 and Mn 30 triads) are upheld also in the present study on the V/Mn triad combinations. These tendencies can very satisfactorily be depicted in diagrammatic form as shown in Fig.…”

Chemistry of Unsaturated Group 6 Metal Complexes with Bridging Hydroxy and Methoxycarbyne Ligands. 1. Synthesis, Structure, and Bonding of 30-Electron Complexes

“…The electronic structure of face-sharing bioctahedral complexes has received considerable attention from computational chemists, which, however, have been mainly concerned with non-organometallic compounds . The metal−metal bonding in these systems follows from the occupation of one σ- and two δ-bonding MOs.…”

Periodic trends in metal–metal interactions in face-shared [M2Cl9]z−systems

“…In fact, these trends were used to design [V 2 (S(CH 3 ) 2 ) 3 Cl 6 ] 2− , the only faceshared complex involving a first row transition metal predicted to have a metal-metal triple bond. 27…”