Relations between Electronic Absorption Spectra and Spatial Configurations of Conjugated Systems. I. Biphenyl

Abstract

Abstract 1) The ultraviolet absorption spectra of biphenyl in the crystalline state, in the solution state, and in the vapor state have been discussed in detail. 2) The relation between the position of conjugation band in the spectra of biphenyl and the spatial configuration of the molecule has been clarified by calculations based on the simple LCAO molecular orbital method. 3) By using the results of the calculations, it has been inferred from the analysis of the absorption spectra that the angles between the planes of the two benzene rings in the most probable conformations of biphenyl in the solution state and in the vapor state are about 20°C and about 40∼43°C, respectively. These values coincide fairly well with the values estimated by other workers on different grounds.