Photolysis of [Co(NH3)5Br]2+ at 254 and 313 mn in Ethylene Glycol-Water, Glycerol-Water and Acetonitrile-Water Mixed Solvent Systems

Chemistry Department, A. B. N. Seal College, Cooch Behar Chemistry Department, Bethune College, Calcutta Dcpartment of Chemical Technology, University College of Science and Technology, University of Calcutta, Calcutta-700 009 Manuscript received 3 January 1994, accepted 29 March 1994 Photolysis of [Co(NH3)5Br]2+ by uv radiations in aquo-organic solvent systems of various compositions reveals that the efficiency of the intramolecular photoredox reaction, as manifested in the quantum yield of Co2+, varies in a complex way and no single factor appears capable of explaining all the features of the photolytic behaviour of the complex. The present work tries to explain the variation of ΦCo2+, with composition in mixed solvent systems like ethylene glycol-water, glycerol-water and acetonitrile-water in terms of dielectric constant, viscosity, critical solvation and solvent structure effects. The effect of pH variation on ΦCo2+ has also been investigated