Synthesis, structure and properties of three isostructure polymer networks based on mixed ligands

Three isostructure coordination polymers with a general formula: [ML(bbi)(H2O)2]n (M = Co, 1; Zn, 2; Cd, 3) {L = fumaric acid dianion, bbi = 1,4-bis(1H-imidazol-1-yl)butane} have been successfully prepared by adopting liquid diffusion method. Their structures have been determined by single-crystal X-ray diffractions, and further characterized by elemental analysis, FT-IR spectra, Powder X-ray diffractions and thermogravimetric (TGA) studies. The results show that they all possess a three-dimensional (3D) framework constructed by the double helical chains and L dianions and reveal a 3-fold interpenetrating net with a uninodal 4-connected Diamond-related topology. In addition, the photoluminescent properties of 2 and 3 have also been investigated at room temperature.