Reactivity of transition metal dioxide anions MO2− (M = Co, Ni, Cu, Zn) with sulfur dioxide in the gas phase: an experimental and theoretical study

The reactivity of transition metal dioxide anions of cobalt, nickel, copper and zinc with sulfur dioxide has been investigated in the gas phase by mass spectrometric techniques and theoretical calculations. Dioxide anions of the late transition metals Cu and Zn promote an unprecedented fast and efficient oxidation to the sulfate radical anion through a double oxygen transfer, whereas the earlier transition metals Ni and Co only undergo the addition of two SO2 molecules. The ligation of a water molecule to ZnO2radical dot− switches the reaction path to a single oxygen anion transfer, forming SO3radical dot−.