Steric effects and the electrochemistry of phenyl-substituted anthracenes and related compounds

Abstract

The reduction and oxidation potentials of a series of phenylsubstituted anthracenes (9-, 9,10-, 1,9-, 1,10-, 1-, and 2-) and rubrene were determined by polarographic and cyclic voltammetric techniques. These potentials correlate well with those predicted by molecular orbital calculations, based on parameters obtained from the electron spin resonance spectra of the corresponding radical ions. These results lead to the conclusion that structural information, such as the angle between the phenyl substituent and the anthracene nucleus, can be obtained from electrochemical measurements. The mechanism of the protonation reaction following the electron transfer steps is shown to depend upon the electron density distribution and positions of substitution in the radical ions.