Vibrational and electronic spectra of hexacyanobenzene and its electron donor-acceptor complexes

Abstract

Electronic and vibrational spectra of hexacyanobenzene and 35 electron donor-acceptor complexes have been obtained. The values of hν_ct were correlated with the ionization potential of the donor and a linear relationship was obtained with a slope approximating to unity, allowing the determination of the energy of interaction in the excited state. The origin of band splittings is discussed and the most probable reason is the electron transition from various levels of the donor. The vibrational spectra of the complexes exhibit a new band related to the electronic vibration which may be ascribed to the vibration stimulated by the Raman active ν_C–CA_1g mode.