The Activation of Carbon Dioxide by Metai Complexes

Abstract

Chemistry of one-carbon-atom molecules (C 1 chemistry) is an important area of research for the organometallic chemist. The motivation for these efforts stems from the belief that the raw material base for commercial organic chemicals will shift from oil to coal, owing to both economic reasons and declining petroleum reserves. Prior to a discussion of CO 2 insertion reactions into M–H and M–C bonds, it is useful to review some of the known coordination chemistry of carbon dioxide, because the activation of CO 2 by metal centers is assumed to be of significance in most of these processes. In principle, the insertion of CO 2 into a transition-metal hydrogen bond can result in either M–O or M–C bond formation––that is, production of metalloformate or metallocarboxylic acid derivatives. Some very interesting work on the reversible insertion of carbon dioxide into palladium–carbon bonds has been reported recently by Braunstein and coworkers. The reactions of CO 2 , with metal –hydroxides, –alkoxides, and –amides to provide metallobicarbonates, –alkyl carbonates, and –carbarnates in general do not involve activation of carbon dioxide by prior coordination to the metal center. The use of carbon dioxide as an industrial source of chemical carbon has been limited mainly to the production of organic carbonates, carboxylic acids, and ureas. The chapter discusses recent literature relevant to the coordination chemistry of carbon dioxide and its use as a source of chemical carbon.