Molecular complexes of TCNE with phenols

Abstract

Molecular complexes of TCNE with phenols and naphthols have been studied using electronic absorption spectroscopy. All the complexes exhibited two CT bands each. The appearance of two CT bands is attributed to the formation of two isomeric CT complexes, R_x, and R_y differing in the orientation of donor and acceptor molecules. The ionization potentials of highest and penultimate molecular orbitals have been calculated from the position of the CT bands. The stabilities of the complexes with R_y, configuration are found to be greater than those with R_x, configuration. The stabilities of the complexes increased with increasing electron releasing ability of the substituents. In general the stabilities of the phenols-TCNE complexes are found to be greater than those of the TCNE complexes with correspondingly substituted benzenes. This is attributed to the greater polarity of phenols as compared to similarly substituted benzenes.