Orderly progressions in stepwise electrode potentials of 4d and 5d hexafluorometallate complexes in acetonitrile

Abstract

Successive reversible E° values for the redox couples [MF₆]^z/z–1(z= 0, –1, –2) where M = Ta, W, Re, Os and Nb, Mo, (Tc), Ru, detected by cyclic voltammetry in MeCN over a 6 V range, follow linear progressions related to central ion nuclear and electronic structure for d⁰→ d¹, d¹→ d², and d²→ d³ while deviations observed for d³→ d⁴ and subsequent couples are attributable to spin-pairing effects; corresponding 4d^n/n+1 and 5d^n/n+1couples are almost uniformly separated by 1.0 V.