Kyuya Yakushi1, Masaaki Iguchi1, Haruo Kuroda1
1Department of Chemistry, Faculty of Science, The University of Tokyo
Tóm tắt
Abstract
Polarized absorption and reflection spectra were observed on the single crystals of the solventfree and solvent containing modifications of benzidine (BD)–7,7,8,8-tetracyano-p-quinodimethane (TCNQ) molecular complex, by using the microspectrophotometers of transmission and reflection types. The absorption spectra obtained by the dispersion analyses of the reflection spectra agreed fairly well with those directly observed by the transmission method. The spectra showed that the BD–TCNQ, complex has non-ionic ground state in all modifications although the intermolecular interaction is considerably strong and is appreciably affected by the inclusion of solvent molecules. In all modifications, the second charge transfer band was confirmed to be polarized in the direction almost perpendicular to the direction of the donor-acceptor stack, while the first charge transfer band is polarized in the direction of the donor-acceptor stack as it is usually found for a typical charge transfer complex. This anomaly of the polarization direction of the second charge-transfer band was concluded to be due to a strong mixing between the charge-transfer excitation and the local excitation associated with TCNQ.
