Assembly of 1D meso coordination polymer from a chiral mononuclear complex by N-deprotonation of the tris(2-benzimidazolyl) ligand

The one-dimensional (1D) meso polymeric structure {[Cd2(HL)(N3)2(H2O)] · (DMF)3}n 2 has been assembled from a propeller-like chiral mononuclear complex {[Cd(H3L)(H2O)][Cd(H3L)(H2O)2]}(ClO4)4 1 (H3L = tris(5-methyl-2-benzimidazolylmethyl)amine). The assembly process was achieved by the aid of NaN3 which causes N-deprotonation of the 5-methyl-benzimidazole groups and bridges the opposite enantiomers to form 1D meso chain. Both the monomer 1 and polymer 2 have been characterized by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analysis and infrared spectroscopy. The ESI-MS of complex 1 has been studied to understand the assembly process. The photoluminescence measurements of the ligand and the complexes show that the ligand-based emission has been significantly enhanced in the monomer while little changed after polymerization.