Primary photophysical and photochemical processes for Pt(SCN)(6)(2-)complex

Photosolvation of a Pt-IV hexathiocyanate complex Pt(SCN)(6)(2-) in water and ethanol was studied by steady-state photolysis, nanosecond laser flash photolysis, and ultrafast kinetic spectroscopy. Complexes Pt(SCN)(5)(H2O)-and Pt(SCN)(5)(C2H5OH)-were found to be the only reaction products. The quantum yields of photosolvation are independent of the excitation wavelength, being equal to 0.25 and 0.5 for the solutions of the complex in water and ethanol, respectively. Photosolvation proceeds by the mechanism of heterolytic metal-ligand bond dissociation without involvement of redox processes. The characteristic time of formation of the end products for both solvents is about 10 ps. Three successive intermediates detected on the picosecond time scale were interpreted as Pt-IV complexes. The nature of the intermediates and possible mechanisms of photosolvation are discussed.