Activation of dioxygen molecules on dinuclear metal centers

摘要

Activation of dioxygen molecules on transition metal centers, especially dinuclear metal centers was systematically investigated using hydrotris(3,5- dialkylpyrazolyl)borate ligands from both organometallic and bioinorganic viewpoints. Physicochemical data and X-ray crystallography of synthesized dicopper- O2 complexes revealed a μ-η~2:η~2` coordination mode which was proposed as the most probable model of oxyhemocyanin. Dioxygen species bound to dinuclear cobalt and nickel centers are quite active and react rapidly with C-H groups in ligands giving oxygenated products even at room temperature. The stability of (μ-η~2:η~2-O2)M2, complexes depends on the electron-donating ability of the central metal atoms and the difference arises mainly from the extent of back donation to the antibonding O-O orbital .