Organic Electron Transfer Systems, II Substituted Triarylamine Cation‐Radical Redox Systems – Synthesis, Electrochemical and Spectroscopic Properties, Hammet Behavior, and Suitability as Redox Catalysts

Abstract

Abstract 21 triarylamines ( 1n – 1z , 1za , 1zb ) and triarylamine analogs ( 2a , 2b , 3a , 3b , 4a , 4b ) with substituents in at least all three p positions and some of their cation‐radical hexachloroantimonates have been synthesized. The electrochemical behavior has been studied by cyclic voltammetry. Most of the compounds show chemically and electrochemically reversible first oxidation waves in the formation of the cation radicals. With the exception of 4a and 4b , the second wave for the formation of the dication is chemically irreversible. The UV spectra of the triarylamine cation radicals have been obtained in the presence of a slight excess of SbCl 5 . A good Hammett correlation between the first anodic potential of only p‐substituted triarylamines and the σ/σ values has been established. Some redox‐catalytic properties of triarylamine cation radicals are described.