Coordination Polymers Assembled from 3,5-Pyrazoledicarboxytic Acid and Bis(triazolyl) Ligands: Chiral and Meso-Structures Induced by Ligand Flexibility and a Six-Connected Self-Catenated Network

Seven coordination polymers with 3,5-pyrazoledicarboxylic acid (H(3)pdc) and bridging triazolyl ligands, [Ni-3(pdc)(2)(btb)(2)(H2O)(6)](n) (1), [Zn-2(Hpdc)(2)(btb)(H2O)(2)](n) (2), {[Ni-3(pdc)(2)(bth)(H2O)(8)]center dot 2DMF)(n) (3), [Ni(Hpdc)(bth)](n) (4), [Ni-3(pdc)(2)(bth)3(H2O)(4)](n) (5), [Ni(Hpdc)(bth)(H2O)](n) (6), and {[Zn(Hpdc)(bth)(H2O)]center dot 2H(2)O}(n) (7) (btb = 1,4-bis(1,2,4-triazol-1-yl)butane, bth = 1,6-bis(1,2,4-triazol-1-yl)hexane), have been hydrothermally or solvothermally synthesized and structurally characterized. Complexes 1, 3, and 4 are all one-dimensional chain coordination polymers. The structure of 2 comprises herringbone-like two-dimensional 6(3) nets. 5 possesses a six-connected self-penetrated three-dimensional (3D) architecture with 4(4).6(10).8 topological symbol. Complexes 6 and 7 have a similar 3D framework and can be simplified as a four-connected 6(6) topological network. However, because of the flexibility of the bth ligands in conformations, homochiral helical and meso-helical chains are formed by metal ions and bth ligands in 6 and 7, respectively. The magnetic properties of compounds 1, 3,5, and 6 are investigated over the temperature range of 1.8-300 K.