INFRARED-SPECTRA OF TETRAKIS(ALKYLTHIO)TETRATHIAFULVALENES

Infrared spectra were measured for tetrakis (alkylthio) tetrathiafulvalenes (abbreviated TTCn-TTFs (n=1-18)) as powder samples and single crystals. In the compounds with n = 1-26, the stretching vibrational bands of the CH2 and CH3 groups and their relative intensities vary with n. The compounds with n {greater-than or approximate} 7-9 show nearly identical spectra, where the stretching deformation vibrations of the CH2 groups develop and approach those in polyethylene. This observation suggests that the high electrical conduction by the molecular fastener effect in the long-chain compounds of TTCn-TTFs correlates significantly with the development of polyethylene-like alkyl chains in the crystal. © 1990.