Novel binuclear copper(II) complexes of di-2-pyridyl ketone N(4)-methyl, N(4)-phenylthiosemicarbazone: Structural and spectral investigations

Four binuclear complexes [Cu(dptsc)Cl]2 Æ 3H2O (1), [Cu(dptsc)Br]2 (2), [Cu(dptsc)(l-N3)]2 (3) and [Cu(dptsc)(NO3)]2 Æ H2O (4) (where Hdptsc = di-2-pyridyl ketone N(4)-methyl, N(4)-phenylthiosemicarbazone) have been synthesized and physicochemically characterized. Each Cu(II) atom in the monomeric unit exists in a penta-coordinate environment. The molecular structures of [Cu(dptsc)Br]2 and [Cu(dptsc)(l-N3)]2 are resolved by single-crystal X-ray diffraction studies. Both the crystals are centrosymmetric dimers where each ligand unit coordinates through one of the pyridyl nitrogens, azomethine nitrogen and thiolate sulfur to Cu(II). A distorted square pyramidal geometry is observed around Cu(II) for both the complexes, where the N(2) nitrogen of the second ligand unit coordinates to the first Cu(II) center in compound 2 and N(6) nitrogen of the azido group bridges both the Cu(II) centers in compound 3. Spectral characterization corroborate the structural studies.