Crystal and Molecular Structure of Anion Radical Salt (N-Me-DABCO)(TCNQ)2.

An anion radical salt of 7,7,8,8-tetracyanoquinodimethane (TCNQ) with the complex composition (N–Me–DABCO)(TCNQ)₂ (1) has been synthesized. The crystal structure 1 has been characterized by X-ray diffraction. The structure of this salt consists of almost homogeneous stacks of TCNQ particles separated by cation layers. Interplanar spacings of 3.25 and 3.29 Å alternate in the stacks. Due to the alternating distances and uniform charge distribution in the stacks, conducting channels are formed in the structure, which determine the properties of an organic metal or a narrow-gap semiconductor, as confirmed by IR spectra containing electron-phonon interaction-related features. In particular, vibrational lines against the continuous absorption background are observed: the band gap does not exceed 0.06 eV. As a result lines of totally symmetric vibrations appear (without the electron-phonon interaction, these lines are forbidden in the IR spectra). [ABSTRACT FROM AUTHOR]