M= Fe or Ru photochemically, with evolution of CO, to give [R u~(CO),~], from which Na2 [Ru (CO),] is prepared. In principle these reactions again allow a cyclic conversion of C02 to CO, but in practice [Ru~(CO),~] recovery after the photolysis is ineffi~ ient.'~ The literature contains several earlier reports of reactions of transition-metal ions with C02 to give carbonyl complexes or carbonates, but in none of these cases was both carbonyl and carbonate ...
