Electronic structure and redox reactions of vanadium(II) polypyridine, isocyanide, and phosphine complexes
Electronic absorption spectra and redox reactions are reported for a variety of vanadium(II) complexes of strong-field ligands. The absorption spectra of [V(L-L)3]2+ (L-L = polypyridine) are dominated by intense metal-to-ligand charge-transfer (m.l.c.t.) transitions. The m.l.c.t. absorption maxima for [V(L-L)3]2+, and half-wave potentials for reduction of [V(L-L)3]2+, are sensitive to substituents in the polypyridine rings. In contrast, the [V(L-L) 3]3+/2+ redox process is primarily metal-localized. Cyclic voltammetry performed on [V(CNBut)6]2+ shows that the 0, I, II, and III oxidation states are readily accessible; [V(dppe)3] [V(CO)6]2 [dppe = 1,2-bis(diphenyl-phosphino)ethane] exhibits waves attributable to [V(dppe) 3]3+/2+, [V(dppe)3]2+/+, and [V(CO)6]0/-. The lowest-energy spin-allowed electronic transitions in [V(CN But)6]2+ are primarily d-d in nature, whereas those in [V(dppe)3]2+ contain substantial m.l.c.t. character.
Publication Source (Journal or Book title)
Journal of the Chemical Society, Dalton Transactions
Shah, S., & Maverick, A. (1987). Electronic structure and redox reactions of vanadium(II) polypyridine, isocyanide, and phosphine complexes. Journal of the Chemical Society, Dalton Transactions (12), 2881-2884. https://doi.org/10.1039/DT9870002881