Syntheses, Crystal Structures and Photoluminescence Properties of Cadmium(Ⅱ) and Nickel(Ⅱ) Complexes with 2-(2-Benzimidazolyl)quinoline

Two novel complexes, [Cd2(BMQU)2Cl4] (1) and [Ni(BMQU)2HPO4]·1.5H2O (2) (BMQU = 2-(2-benzimidazolyl)quinoline), were synthesized by the hydrothermal method and characterized by elemental analysis, IR, and TG-DTG. The crystal structures were determined by single-crystal X-ray diffraction. Both 1 and 2 crystallize in the triclinic system, space group P . The data for 1: a = 0.8342(7), b = 0.9226(9), c = 1.0646(8) nm, α = 90.819(2), β = 97.466(2), γ = 98.280(2)°. The Cd(Ⅱ) is coordinated with three chlorine atoms and two nitrogen atoms of a BMQU molecule, generating a distorted square-pyramidal geometry. The dinuclear Cd(Ⅱ) complex is formed by two chlorine bridge bonds, and the one-dimensional chain structure is constructed with the hydrogen bond N-H…Cl and π-π stacking interaction. The data for 2: a = 1.2251(1), b = 1.2451(1), c = 1.2868(1) nm, α = 107.510(2), β = 98.630(1), γ = 109.921(2)°. The Ni(Ⅱ) is coordinated with four nitrogen atoms of two BMQU molecules and two oxygen atoms of a HPO42-, forming a distorted-octahedral geometry. The two-dimensional layer structure is formed by the hydrogen bonds and π-π stacking interaction between neighboring molecules. Complex 1 shows a strong blue fluorescence emission (λmax= 456 nm) at solid state.