Thermal and photochemical reactions of chromium (IV)-diperoxo complexes with organic substrates- evidence for hydroxylation of proline and phenol

Abstract

The diperoxo complexes of chromium in an unusual oxidation number viz. 4, react with organic substrates such as proline and phenol to give bydroxyproline and o-benzoquinone as products respectively. The organic products were identified by electronic spectra as well as by their characteristic R₁ values in thin layer chromatography using n-propanol-water(1:1v/v) mixure and chloroform as solvents for proline and phenol reaction products respectively. the studies reveal that the hydroperoxide radicals formed during the decomposition of Cr(IV)-diperoxo complexes give rise to the hydroxylation processes observed. The hydroxylation reactions are facilitated by light and yields of hydroxyproline upto 9% (from proline) have been obtained . The study presents one of the first examples of the use of Cr(IV) systems for biologically relevant processes such as hydroxylation.