Primary photochemical processes of the PtCl 62− complex in alcohols

Abstract

Laser flash photolysis was used to verify whether or not the primary photolysis mechanism of the PtCl 6 2− complex in ethanol and isopropanol was the same as that found previously in methanol (V. P. Grivin, J. Photochem. Photobiol. A: Chem., 51 (1990) 167, 371, 379). The primary process is the electron transfer from an alcohol molecule to the excited complex. The trivalent platinum complex and the solvent radical form the primary radical complex PtCl 6 3− …Ṙ. At room temperature, this radical complex dissociates yielding PtCl 6 3−, which further dissociates either photochemically after absorption of a photon or thermally, yielding PtCl 6 2− and Cl −. The high quantum efficiency of photodissociation results in a non-linear of PtCl 6 3− and PtCl 6 2− yield vs. laser pulse intensity. At low temperatures, the PtCl 6 3− …Ṙ radical complex either decays during the second electron transfer from the radical to the platinum ion yielding the final complex PtCl 4 2− or forms, in the presence of oxygen, a new radical complex PtCl 6 3− …RȮ 2.