Syntheses, crystal structures, and properties of four coordination polymers with a new bifunctional ligand

Four new coordination polymers, {[Cd2(L)2·H2O]·4DMF·14H2O}n (1), {[Cd (L)]·2DMF·6H2O}n (2), {[Zn2(L)2]·4DMF·5H2O}n (3) and {[Cu (L)]·2DMF}n (4) (H2L = 2,5-bis((4H-1,2,4-triazol-4-yl)carbamoyl)terephthalic acid), have been synthesized under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction. All of them exhibit three-dimensional structures possessing one-dimensional channels filled with solvent molecules. 1 is a 3D framework with large 1D channels (6.60 × 8.56 Å2) filled with free DMF molecules and the 3D structure of 1 is a new (4, 8) network with Schläfli symbol {416.612}{44.62}2. 2 and 3 with different metal centers have similar structure except for the numbers of free water molecules. They both feature a (4, 4)-connected 3D network of {65.10} {65.8} topology with left- and right-handed helical chains along b-axis. While 4 is a 3D framework with typical CdSO4 topology. In addition, 1–3 show strong fluorescent emissions at room temperature, which can be assigned to the ligand-to-ligand charge transfer (LLCT) emissions.

Four new metal–organic frameworks display interesting 3D structures have been synthesized based on a novel organic ligand (H2L) involving both 1,2,4-triazole and carboxylic groups under solvothermal conditions. Compounds 1–3 display intense fluorescent emissions at 435, 444 and 445 nm, respectively.Figure optionsDownload as PowerPoint slide