ABSTRACT
The temperature and polarization dependence of the optical reflectivity spectra of a quasi-one-dimensional 1/4-filled band system, (DMEDO-EBDT)(2)PF(6), have been investigated. We observed clear anisotropy in the electronic structures corresponding to the anisotropic transport properties. The appearance of a charge gap (E(g) > 0.1 eV) and transfer of the spectral weight accompanied by the metal-insulator phase transition were clearly observed. In addition, a split of the intramolecular vibrational modes was observed, which strongly suggested the existence of charge disproportionation in the low temperature phase. We also observed a photoinduced reflectivity change, which implied the occurrence of a photoinduced phase transition from the low temperature insulating phase to the high temperature metallic phase.
ABSTRACT
Lower oxidation potentials than for the monomeric starting materials are displayed by the diporphyrins obtained by one-electron oxidation with tris(4-bromophenyl)ammonium hexachloroantimonate [see, for example, Eq. (1)]. This and the strong red shift observed for the Soret bands of the product are indicative of extensively delocalized pi-electron systems in the fused diporphyrin. Ar=3,5-di-tert-butylphenyl.
