The effect of solvent mobility on Cr(NH3)(2)(NCS)(4)(-) photolysis

The photolysis yields and E-2 relaxation rates of Cr(NH3)(2)(NCS)(4)(-) in ethanol, propanediol and glycerol have been obtained as a function of temperature. As in the case of acetone solutions there is a fast photoprocess that persists at low temperatures where independent measurements indicate no solvent motion. The onset of the slow photoreaction in ethanol begins only after solvent motions are fast on the time-scale of the E-2 level decay. In contrast, both the E-2 depopulation and the slow photolysis in propanediol and glycerol are induced by solvent movement. The E-2 relaxation rate and the photolysis yield increases in ethanol occur at the same temperature but the two processes are enhanced by different solvent motions in glycerol.