Three new 3D coordination polymers constructed by biphenyl-2,2′,4,4′-tetracarboxylic acid: Effect of metal ions and the second ligands

Abstract

Three new coordination polymers with different architectures, {[Zn 2(bta)(2,2′-bipy) 2]·H 2O} n ( 1), {[Cd 2(bta)(2,2′-bipy) 2(H 2O)]·H 2O} n ( 2) and [Cd 3(bta)(Hbiim) 2(H 2biim)] n ( 3), where H 4bta = biphenyl-2,2′,4,4′-tetracarboxylic acid, 2,2′-bipy = 2,2′-bipyridine and H 2biim = 1 H,1′ H-2,2′-biimidazole, have been obtained by the reactions of metal nitrates, H 4bta, the second ligands and H 2O under similar hydrothermal conditions. All the polymers are three-dimensional (3D) constructions with different networks, in which 1, 2 and 3 exhibit a (4 2·8 4)- pts, (4 2·6 3·8)- sra and (4 16·6 5) topology, respectively. The bta ligands in 1– 3 adopt η 6,μ 6-hexadentate, η 8,μ 5-tetradentate and η 10,μ 7-decadaldentate coordination modes, respectively, and the corresponding angles of two benzene rings in the ligand of each compound are 45.96°, 54.93° and 52.50°, respectively. This study indicates that the natures of metal ions and the second ligands are crucial factors for self-assemble of coordination polymers.