DIVERSITY IN PHOTOREDOX CHEMISTRY OF OXO OR HYDROXO COMPLEXES OF S(2)METAL-IONS

The electronic spectra of hydroxo or oxo complexes of the s(2) metal i ons Tl+, Sn2+, Sb3+, Bi3+ and Te4+ in alkaline solutions display absor ption bands in the UV region which are assigned to metal-centered sp t ransitions. In the case of Tl+ and Sn2+ + these sp-excited states are also luminescent. TlOH is photooxidized to Tl2O3 by molecular oxygen w hile the photooxidation of Sn(OH)(3)(-) to Sn(OH)(6)(2-) is even achie ved by water which is reduced to hydrogen. Both complexes produce hydr ated electrons upon 266 nm laser excitation. No electron ejection can be observed for the hydroxo or oxo metalates of Sb3+, Bi3+ and Te4+, w hich undergo a photoreduction to the metallic state with a concomitant oxidation of hydroxide to hydrogen peroxide and/or oxygen.