Syntheses, structures and catalytic activities of dinuclear copper complexes with tetradentate diaminebis (phenolate) ligands

摘要: Two new Cu(II) complexes were synthesized from Cu(NO3)2·3H2O and salan ligands, H2[H4]L1 H2[H4]L2 (H2[H4]L1 = N,N′-bis(o-hydroxybenzyl)-1,2-diaminocyclohexane; H2[H4]L2 = N,N′-bis(o-hydroxybromobenzyl)1,2-diaminocyclohexane). They characterized by various spectroscopic methods structures of the determined X-ray diffraction analyses. Interestingly, coordinates to copper centers as monoanionic in a tetradentate mode complex 1, [Cu(H[H4]L1)]2·2NO3·2H2O, whereas behaves dianionic ligand 2, [Cu([H4]L2)]2·0.4H2O, via O,N,N′,O′-donor atoms. The asymmetric unit is dimerized about center inversion bridging phenoxide-O atom between two metal centers. electronic spectra studies solvents with different coordination numbers proved stability dinuclear other than DMSO DMF. Complexes 1 2 showed high catalytic activities good-to-excellent selectivities oxidation olefins, benzyl alcohol ethyl benzene H2O2 acetonitrile. A probable mechanism discussed.