Cotton Effect Induced in Optically Inactive Molecules and Molecular Complexes by Optically Active Environment. I. Pyrene, TCNNQ, and Their Molecular Complex in Acetylcellulose Film

Abstract

Abstract Ultraviolet absorption spectra, induced optical rotatory dispersion and circular dichroism of pyrene, TCNNQ, and their molecular complex were measured in acetylcellulose film and solution. The Cotton effect corresponding to each absorption maximum of these systems appeared. A perturbation of excited states of these molecules and their complex due to an asymmetric environment of acetylcellulose might be of paramount importance in producing a non-zero rotational strength in the corresponding molecular absorption region. The second charge-transfer band was clearly detected in the differential optical rotatory dispersion spectrum of the TCNNQ-pyrene molecular complex embedded in an acetylcellulose film. The method was shown to be promising in detecting very weak and closely overlapped transitions in various molecules.