Increasing the oxidation power of TCNQ by coordination of B(C ₆ F ₅ ) ₃

Abstract

The oxidation power of the cyanocarbon TCNQ (tetracyano-quinodimethane) can be significantly increased to approximately <i>E</i> = +0.9 V <i>vs.</i> Cp₂Fe by coordination of up to four equivalents of the strong fluorinated Lewis acid B(C₆F₅)₃, resulting in a highly reactive but easy-to-use oxidation system. Thianthrene and tris(4-bromophenyl)amine were oxidized to the corresponding radical cations. Dianionic [TCNQ·4 B(C₆F₅)₃]^2- was formed upon reduction with two equivalents of ferrocene or decamethylcobaltocene. [TCNQ·4 B(C₆F₅)₃]^- and [TCNQ·4 B(C₆F₅)₃]^2- are rare cases of redox-active weakly-coordinating anions.