Theoretical study of the COLin complexes: Interaction between carbon monoxide and lithium clusters of different sizes

Abstract

A theoretical study was carried out about the complexes composed of carbon monoxide and small lithium clusters, namely COLi2, COLi4, COLi6, COLi8, COLi5+, and COLi7+. The complexation of carbon monoxide with Li2 is found to be endothermic and not spontaneous. As for Li4 and Li5+, they can only reduce CO to single bond length. By comparison with the N2Lin complexes where a minimum of eight lithium atoms are needed to cleave the triple bonded nitrogen completely, the Lin cluster behaves more efficiently in activating the CO molecule because the Li6 cluster is sufficient to cleave the CO triple bond in a highly exothermic way. Besides, the degree of reduction of CO gradually increases with Lin becoming larger, and the Li7+ and Li8 clusters can cleave the CO triple bond to greater extent than Li6 does. Due to the ability of lithium clusters to cleave the NN and CO triple bonds in effective ways, they offer a promising approach to activate other strong chemical bonds.