Luminescence spectra of the mixed complexes [TcClxBr6–x]2–

Abstract

Reaction of [TcCl₆]^2– with aqueous HBr followed by rapid precipitation of Cs₂[SnCl₆] from the solution produces homogeneous crystalline solids which luminesce strongly under blue or ultraviolet excitation. Analysis of the spectra obtained at low temperatures with selective excitation shows the presence of nine of the ten expected stereoisomers of [TcCl_xBr_6–x]^2–(x= 0–6). Similar results may be obtained by starting with [TcBr₆]^2– in aqueous HCl. There is no evidence for the dominance of a trans effect in the substitution reaction.