Syntheses, Structures, and Luminescent Properties of Two Novel Coordination Polymers with Poly-Carboxylate and N-Heterocyclic Ligands

Two novel metal–organic coordination polymers {[Pb(CIPT)(1,4-BDC)]·2H2O}n1 and {[Zn2(IPDT)2(1,4-BDC)2(H2O)].3H2O}n2 [CIPT = 2-(3-chlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline, 1,4-BDC = terephthalic acid, IPDT = 4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)-2,6-dimethoxyphenol] were obtained from hydrothermal reaction and characterized by elemental analysis, thermogravimetric (TG) analysis, IR and single-crystal X-ray diffraction. Both of the two coordination polymers exhibit one-dimensional (1D) infinite chain structures through non-covalent interactions, and the existence of hydrogen bonds interactions lead the 1D chain to 2D layer structures. It is noteworthy that the existence of hydrogen bonds reinforces the structural stability of the complexes 1 and 2, which can be proved by TG analysis. The photoluminescent study of coordination polymer 1 shows that it exhibits fluorescent emission band at 637 nm, which is red-shifted by 46 nm relative to the free ligand CIPT.