Activation Of Carbon Dioxide By Formation Of Metalloheterocycles And Metallocycles PDF Download

The objective of this project was to find new ways to incorporate carbon dioxide into organic molecules by activation of the carbon dioxide within the coordination sphere of an electron rich transition metal complex. Achievements included the discovery that heteroallenes characteristically undergo reductive disproportionation with dianionic carbonyl metals and can add to electron rich - neutral carbonyl complexes such as W(eta(5)-C5H5)2(CO) to give metalloheterocycles. We have further observed that unsaturated ligands can be induced to couple with carbon dioxide by reducing the metal center so that it will activate the carbon dioxide, as exemplified by bis-carboxylation of the carbene or carbenoid ligand in the two electron reduction products of Fischer carbene complexes with phosphine substituents to give substituted malonates, and by endo carboxylation of the eta(4)arene in the Cr( -II) complex Cr(eta(4)-C6H6)(CO)32-. We have also prepared KCo(2,6- C6H3NC)4, the first example of a homoleptic isonitrile complex of a metal in a negative oxidation state and the antecedent for a new class of transition metal complexes. jg p.1.