Synthesis, characterization, spectroscopic and thermodynamic studies of charge transfer interaction of a new water-soluble cobalt(II) Schiff base complex with imidazole derivatives

The water-soluble cobalt(II) tetradentate Schiff base complex [Co(II)L](ClO4)2, L: (N,N′-bis{5-[(triphenylphosphonium)-methyl]salicylidine}-o-phenylenediamineperchlorate has been synthesized and characterized. This complex forms charge transfer (CT) complexes with imidazole and 1-methylimidazole. The formation constant, molar absorptivity (ɛ′), and thermodynamic parameters for charge transfer complexes formation of cobalt(II) Schiff base complexes with imidazole derivatives were determined by using UV–vis spectrophotometric method in aqueous solutions at constant ionic strength (I = 0.2 mol dm−3 KNO3) at pH 6.0 and various temperatures between 292 and 315 K.