Spectroelectrochemical characterization of polyselenide ions in N,N-dimethylacetamide

Abstract

Polyselenide ions formed by the reduction of variable amounts of electrodeposited selenium on a gold grid cathode have been studied in N,N-dimethylacetamide by voltammetry coupled with UV-visible absorption spectrophotometry. Grey selenium reduces in three successive steps to the stable ions Se₈^2- (λ_max=648, 453, 398 and 260 nm), Se₆^2- (λ_max=598, 440 and 260 nm) and Se₄^2- (λ_max=550, 417, 307 and 260 nm). Temperature and concentration effects gave no evidence to suggest the dissociation of Se_x^2- species, in particular Se₆^2-→Se₃^•-.