Syntheses, structures, and properties of copper and cadmium complexes with quinoline-based benzimidazole

A new tridentate ligand 2-((quinolin-8-yloxy)methyl)benzimidazole (L) and three coordination compounds, [CuLCl2] (1), [CuL(H2O)(SO4) center dot 2H2O]n (2), and {[Cd2L2Cl4][CdLCl2(H2O)]2} center dot H2O (3), have been synthesized and characterized. Single crystal structure analyses reveal extensive intermolecular hydrogen bonding, resulting in generation of 1-D-3-D supramolecular networks. Compounds 1 and 2 constitute the first examples of Cu complexes containing both 8-hydroxyquinoline and benzimidazole, while 3 represents the first Cd complex bearing this ligand. Complexes 1-3 show similar quasi-reversible electrochemical behaviors. Complex 2 exhibits a predominantly ferromagnetic interaction between copper centers, and 3 has good fluorescence and can be used as an optical material.