Anion directed cation templated synthesis of three ternary copper(II) complexes with a monocondensed N2O donor Schiff base and different pseudohalides

Abstract

Three copper(II) complexes, [Cu2(L)2(μ1,1-N3)2] (1), [Cu2(L)2(μ1,1-NCO)2] (2) and [Cu(L)(μ1,5-dca)]n (3), where HL is a tridentate mono-condensed Schiff base, 1-(2-aminoethyliminomethyl)naphthalen-2-ol, and dca is dicyanamide, have been prepared and characterized by elemental analysis, IR, UV–Vis and fluorescence spectroscopy and single crystal X-ray diffraction studies. The Schiff base ligand was prepared by a counter anion mediated copper(II) templated synthesis. The azide ligand in complex 1 and the cyanate ligand in complex 2 show μ-1,1 bridging modes, whereas the dca ligand shows the μ-1,5 bridging mode in complex 3. Three equatorial positions of copper(II) are occupied by the tridentate Schiff bases in all three complexes. The fourth equatorial sites are occupied by nitrogen atoms of azide in 1, cyanate in 2 and dca in 3. Another nitrogen atom from a symmetry related pseudohalide coordinates in the axial position of copper(II) to complete its square pyramidal geometry in each of the complexes. Significant supramolecular interactions are observed in all the complexes. Variable temperature magnetic measurements indicate antiferromagnetic interactions between the copper(II) centers in all three complexes.