BIMETALLIC REACTIVITY - SYNTHESIS, STRUCTURE, AND REACTIVITY OF HOMOBIMETALLIC AND HETEROBIMETALLIC COMPLEXES OF A BINUCLEATING MACROCYCLIC LIGAND CONTAINING 6-COORDINATION AND 4-COORDINATION SITES

A binucleating macrocyclic ligand which embodies 6- and 4-coordinate sites has been prepared. Both homobimetallic and site-specific heterobimetallic complexes of Zn(II), Co(II), and Mn(II) have been isolated and characterized. The dimanganese(II) species reacts with dioxygen to give a mixed-valence compound containing both Mn(II) and Mn(III). All of the manganese-containing complexes are effective catalysts for the oxygenation of styrene using iodosobenzene. Crystal structures of these bimetallic complexes confirm the overall structures but also reveal that the 6-coordinate site has an unsymmetrical arrangement of ligands Possibly due to macrocyclic strain. The results from these studies suggest modifications which may result in metal cooperativity in dioxygen uptake and for catalytic epoxidation.