Assembly of two luminescent cadmium(ii) 4,4-phosphini co-dibenzoate coordination polymers

Two new cadmium(II) coordination polymers [Cd(HL)(H2O)]center dot 1.5H(2)O (1) and [Cd(HL)(4-bpmp)0.5]center dot 2H(2)O (2) (H3L = 4,4'-phosphinicobis-dibenzoic acid, and 4-bpmp = N,N'-bis(4-pyridylmethyl)piperazine) have been synthesized by self-assembly of CdCl2 with 4,4'-phosphinicobis-dibenzoate, and N,N'-bis(4-pyridylmethyl)piperazine through solvothermal/hydrothermal method. Their structures were confirmed by X-ray single crystal diffraction, infrared spectrometer (IR), and powder X-ray diffraction (PXRD) and TGA techniques. Both compounds are in Pi space group and exhibited a 2D networks constructed from dinuclear [Cd-2(POO)(2)] or paddle-wheel [Cd-2(COO)(2)(POO)(2)] units, respectively. In 2, the Cd2+ is five-coordinated and shows a rare tetragonal pyramidal geometry. At room temperature, the compounds exhibit moderately intense blue and green fluorescence emission with peaks at 381 nm and 509 nm, respectively.