Syntheses and crystal structures of copper(II), zinc(II) and cadmium(II) complexes containing pyridine, quinoline and 2-methylquinoline

Abstract

Nine new complexes, Cu(L1)2(py)2·H2O (1) [L1=3-(4-methoxyphenyl)acrylate, py=pyridine], Cd(L2)2(py)3 (2) [L2=2-methyl-2-phenoxypropionate], Cd(L3)2(mql)2 (3) [L3=3,4-(methylenedioxy)benzoate, mql=2-methylquinoline], Cu(py)2(L4)2·H2O (4) [L4=2-chloronicotinate], Zn(L5)0.5(py) (5) [L5=butane-1,2,3,4-tetracarboxylate], [Zn(L6)2(ql)]2 (6) [ql=quinoline, L6=(4-chloro-phenoxy)-acetate], [Zn(L7)2(H2O)2](mql)2 (7) [L7=2-hydroxy-5-(phenyldiazenyl)benzoate], [Cd(L7)2(H2O)2](mql)2 (8) and [Zn(ql)2(H2O)4]·(L8)·(H2O)2 (9) [L8=naphthalene-1,5-disulfonate], have been synthesized from an alcohol solution at room temperature and characterized by EA, IR, TGA and single-crystal X-ray diffraction. X-ray crystallographic studies show that these complexes display mononuclear, dinuclear to polymeric chain structures with an octahedral arrangement around the cadmium ions, square-pyramidal coordination geometry around the Cu ion and square-pyramidal/octahedral coordination for the Zn ions. In 1, 4 and 8, the carboxylates are monodentate ligands, while in 2 the carboxylate groups functioned as both monodentate and chelating bidentate ligands. In 3 and 7 the carboxylates are chelating bidentate ligands, the carboxylates in 5 act as a tetra-chelating bidentate ligand and the carboxylates in 6 function as a bridging bidentate ligand. The anions in 9 act as a counter ion. Rich intra- and inter-molecular weak interactions, such as classical hydrogen bonds, CH–Cl, C–H⋯O, CH2⋯O, CH3–O, Cl–O, Cl–π, C–H⋯π, CH3–π and π–π interactions, have been analyzed.