[Charge-transfer compounds based on TCNQ: synthesis and spectroscopic properties]

Charge-transfer materials based on organic donors and acceptors have been under investigation, beginning with the first reports of conducting salts of organocyanide acceptors such as TCNQ. Charge-transfer compounds of the pi-electron acceptor 7,7,8,8,-tetracyanoquinodimethane (TCNQ) show unusual electrical and magnetic properties. The form of TCNQ has a dramatic effect on the properties of the kinds of charge-transfer compounds. In order to further study the vibrational spectroscopy of the organic semiconductor, two kinds of (1:1) charge transfer compounds of TCNQ and [RBz(4-CH3)Py][TCNQ](R==Br(1), I (2)) were synthesized and characterized by elemental analysis, infrared spectrum and Raman spectrum. The tested results of elementary analysis of the charge transfer compounds (1) and (2) were consistent with theoretical values. The IR and Raman spectra of (1) and (2) which indicate the presence of a type of TCNQ species, general speaking, the C[triple bond]N stretching frequencies around 2200 cm(-1), were used to determine the average charge on the TCNQ units, v(CN)for the neutral TCNQ molecule is higher than 2200 cm(-1)), however, v(CN) for the compounds is from 2185 to 2156 cm(-1), both shift to lower frequencies, which were consistent with the frequencies of the TCNQ radical anion In conclusion, the results of IR and Raman spectrum were consistent with the TCNQ radical anion in the compounds, namely TCNQ-.