Photoinduced Charge-Transfer Association of Tetracyanoquinodimethane with Aminobiphenyls

Abstract

The molecular association of acceptors with electron donors is studied in the highly-polar solvent CH 3 CN. Tetracyanoquinodimethane (TCNQ) forms a stable charge-transfer complex with donor molecules such as 4-aminobiphenyl (4-AB), benzidine (BD) and 2-aminobiphenyl (2-AB) with high association constants. The complexes of TCNQ with 4-AB or BD show new absorption bands at around 800 and 500 nm, which can be identified as reduced TCNQ•− and TCNQ 2− species, respectively. These bands grow quickly upon photoirradiation, implying that the charge-transfer complexes are easily formed in an excited state. Conversely, a small spectral manifestation of the charge transfer was observed in the case of 2-AB complex. It is demonstrated that the structural orientation between the geminate ion pairs could play an important role in building a stable complex.

Micro/Nano Crystal Composed of Tetrathiafulvalene–Tetracyanoquinodimethane Prepared Using a Charge Transfer-Induced Reprecipitation Method

“…The TCNQ dispersion had an absorption centered at 397 nm and 550-900 nm, which can be attributed to the neutral TCNQ and TCNQ anion radicals, respectively. [23][24][25][26][27][28] Unlike the pure TTF and TCNQ dispersions, both TTF-TCNQ dispersions prepared in two different processes exhibited a broad absorption extending to a long wavelength of >1000 nm. The broad absorption band in the long wavelength region, which clearly indicated the formation of the TTF-TCNQ CTC by our CtRP method, was assigned to the charge transfer absorption.…”