PHOTOINDUCED OXYGENATION OF TRANS-AQUOHYDRIDOTETRAAMMINERHODIUM(III) - EVIDENCE FOR A TRANSITION-METAL CHAIN CARRIER

Ultraviolet excitations of aerated, acidic aqueous solutions of Rh(NH3)4(OH2)H2+ result in the efficient formation of Rh(NH3)4(OH2)O2H2+. The rate of formation of hydroperoxide was found to be zero order in O2 but first order in both substrate concentration and incident light intensity. The photoinitiated thermal reaction appears to be a chain reaction with Rh(NH3)42+(aq) acting as a chain carrier which “activates” O2 by coordination. The hydroperoxo complex decomposes very slowly, even in the presence of excess Rh(NH3)4(OH2)H2+, to form a colored, paramagnetic species identified as a superoxo complex. © 1979, American Chemical Society. All rights reserved.