Syntheses, crystal structures, and photoluminescence of two Cd(II) complexes with simple ligands

Two cadmium complexes, {[Cd-2(2,5-tda)(2)(ip)(4)]4H(2)O}(n) (1) and {[Cd-2(4,4-obb)(2)(ip)(2)H2O]H2O}(n) (2) (2,5-tda=thiophene-2,5-dicarboxylic acid, 4,4-obb=4,4-oxybisbenzoic acid, ip=1H-imidazo[4,5-f][1, 10]-phenanthroline), were synthesized and characterized by IR, elemental analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. X-ray analysis revealed that 1 is a dinuclear complex with the 2,5-tda anion connecting two Cd ions in a (1)-(1):(0)/(1)-(1):(0) coordination mode. Each dinuclear complex is further connected with neighboring complexes via hydrogen-bonding interactions. Compound 2 displays a 2-D layer structure with opened windows occupied by crystallographic water molecules. The layers are further packed via hydrogen-bonding interactions. Luminescent properties for 1 and 2 are also investigated in the solid state at room temperature.