Three transition metal complexes with 3,5-bis((4′-carboxylbenzyl)oxy)benzoic acid and 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine: Syntheses, structures and properties

Abstract

ABSTRACTThree transition metal complexes, [Cu(PYTPY)2]·Hbcb·2H2O (1), [Ni(PYTPY)2]·Hbcb·2H2O (2) and [Cd(H2bcb)2(PYTPY)] (3) [where, H3bcb = 3,5-bis((4’-carboxylbenzyl)oxy)benzoic acid, PYTPY = 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine], were synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analyses reveal that the complexes 1 and 2 crystallize in the same monoclinic P2(1)/n space group with similar cell parameters. In complexes 1 or 2, an asymmetric unit contains one Cu2+/Ni2+ ion, two PYTPY ligands, one free Hbcb2− ligand and two free water molecules. The metal center is six-coordinate via six nitrogen atoms derived from two different PYTPY ligands in a distorted octahedral coordination geometry. The isostructural complexes 1 and 2 exhibit two dimensional supramolecular layer structures based on c-π stacking interactions and hydrogen bonds. And the complex 3 crystallize in the triclinic P-1 space group. The discrete unit of 3 consists of one Cd2+ ion, two H2bcb− and one PYTPY molecule. Each Cd2+ ion is six-coordinated by three carboxylate oxygen atoms from two different H2bcb− ligands, and three nitrogen atoms from one PYTPY molecule. Zero dimensional structure of 3 is also further extended by π-π interactions and hydrogen bonds to form three dimensional supramolecular network. Furthermore, the complexes 1 and 2 exhibit relevant magnetic properties, and the complex 3 exhibit photoluminescence at room temperature in the solid state.