Synthesis,Crystal Structure,and Magnetic Properties of a Quasi-one-dimensional Compound Based on TCNQ

A novel compound, (IBzQ1)(TCNQ)2 2 (IBzQ1 = 1-(4-iodobenzyl)quinolinium and TCNQ = 7,7,8,8-tetracyanoquinodimethane) has been fabricated and X-ray single-crystal structurally analyzed. This compound crystallizes in the triclinic system, space group Pi with a = 8.3540(17), b = 13.284(3), c = 16.185(3) A, α= 82.12(3),β = 75.19(3), γ= 72.34°, V= 1651.2(6) A3 Z = 2, C40H21IN9, Mr = 754.56, Dc = 1.518 g/cm3,μ = 1.015 mm-1, S = 1.010, F(000) = 754, R = 0.0387 and wR = 0.0948. The structure analysis shows that the anions are stacked into column with tetrads, and there are two types of TCNQ entries (TCNQ-1 and TCNQ0) in agreement with the IR spectra analysis of the compound. The temperature dependence of the magnetic susceptibility (2～300 K) for 2 exhibits spin gap of singlet-triplet feature, and the best fit gave △/kB = 1523.4 K. In order to understand both magnetic behavior and local charge distribution of (TCNQ)2]- unit, the molecular orbital calculations and analysis based on extended Huckel method were performed, and the results support the analyses of both crystal structure and IR spectra.