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

Abstract

Seven coordination polymers with 3,5-pyrazoledicarboxylic acid (H 3 pdc) and bridging triazolyl ligands, [Ni 3 (pdc) 2 (btb) 2 (H 2 O) 6 ] n ( 1 ), [Zn 2 (Hpdc) 2 (btb)(H 2 O) 2 ] n ( 2 ), {[Ni 3 (pdc) 2 (bth)(H 2 O) 8 ]·2DMF} n ( 3 ), [Ni(Hpdc)(bth)] n ( 4 ), [Ni 3 (pdc) 2 (bth) 3 (H 2 O) 4 ] n ( 5 ), [Ni(Hpdc)(bth)(H 2 O)] n ( 6 ), and {[Zn(Hpdc)(bth)(H 2 O)]·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.