Photochemistry of hexachloroosmate(IV) in ethanol

The photochemistry of the Os IV Cl 6 2− complex in ethanol was studied by means of stationary photolysis, nanosecond laser flash photolysis, ultrafast pump-probe spectroscopy and quantum chemistry. The direction of the photochemical process was found to be wavelength-dependent. Irradiation in the region of the d-d and LMCT bands results in the photosolvation (with the wavelength-dependent quantum yield) and photoreduction of Os( iv ) to Os( iii ), correspondingly. The characteristic time of photosolvation is ca. 40 ps. Photoreduction occurs in the micro- and millisecond time domains via several Os( iii ) intermediates. The nature of intermediates and the possible mechanisms of photoreduction are discussed. We believe that the lability of the photochemically produced Os( iv ) and Os( iii ) intermediates determines the synthetic potential of Os IV Cl 6 2− photochemistry. A mechanistic study of the Os IV Cl 6 2− complex photochemistry in ethanol was performed.