VOLTAMMETRIC AND PHOTOELECTROCHEMICAL MEASUREMENTS OF CARBENIUM SALTS HAVING SOME METHOXYPHENYL GROUPS AT AN ITO ELECTRODE

摘要

Triarylcarbenium salts, Φ~a_3C~+, Φ~b_3C~+, Φ~fΦ~b_2C~+, Φ~eΦ~b_2C~+, and PhΦ~b_2C~+, [Φ~a, Φ~b, Φ~e, Φ~f, Ph = 2,4,6-(MeO)_3C_6H_2, 2,6-(MeO)_2C_6H_3, 2-(MeO)C_6H_4, 4-(MeO)C_6H_4, C_6H_5] showed a reversible redox wave with one electron transfer at an ITO electrode in 1,2-dichloroethane. The wide range of the cathodic shift in the redox potentials over 580 mV could be observed as the number of o- and p-methoxy groups increased. It seems probable that the electron donation from the o- and p-methoxy substituents to the central carbon causes such a wide negative shift in the redox potentials. The increase of a cathodic current was observed, upon illumination, by the all salts tested under cathodic polarization. The magnitude of the cathodic photocurrent increased with increasing cathodic potentials, and reached a plateau.