Tetra-, penta- and hexa-coordinated transition metal complexes constructed from coumarin-containing N2O2 ligand

Abstract

Three newly designed complexes, [Cu(L)]·CHCl3 (1), [Co(L)(MeOH)]·CHCl3 (2) and [{Ni(L)(MeOH)(PhCOO)}2Ni] (3) a coumarin-containing Salamo-type chelating ligand (H2L) have been synthesized and characterized by elemental analyses, IR and UV-VIS spectra, and X-ray crystallography. Complex 1 includes one Cu(II) atom, one completely deprotonated (L)2− unit and one crystalling chloroform molecule, the Cu(II) atom shows a square-planar geometry. Complex 2 includes one Co(II) atom, one completely deprotonated (L)2− unit, one coordinated methanol molecule and one crystalling chloroform molecule. The Co(II) atom is a distorted trigonal-bipyramidal geometry. While complex 3 includes three Ni(II) atoms, two completely deprotonated (L)2− units, two benzoates and two coordinated methanol molecules. The complexes 1 and 2 are both possess three-dimensional supra-molecular structures by abundant noncovalent interactions. But, complex 3 formed a two-dimensional supra-molecular structure by intra-molecular hydrogen bonds. In addition, the antimicrobial and fluorescence properties of H2L and its complexes 1, 2 and 3 were also investigated.