A series of transition coordination polymers assembled by asymmetric dicarboxylic acid and flexible bridging ligand: Structural diversities, topologies and properties

Abstract

By employing asymmetric dicarboxylate and flexible N-donor ligands, four new coordination polymers, namely, Zn(ptmb)0.5(hpht)(H2O) (1), Cd2(ptmb)0.5(hpht)2(H2O) (2), [Co(ptmb)0.5(hpht)(H2O)2]·H2O (3), [Ni(ptmb)(hpht)(H2O)2]·H2O (4), (ptmb=1,4-bis(1,2,4-triazol-1-yl-methyl)benzene and H2hpht=homophthalic acid) have been synthesized. The networks feature diverse structures and coordination modes at the metal ions. Complex 1 is a deeply corrugated 2D layer structure of hcb topology, while the complex 2 presents the example of 3D sxd topological architecture. Complex 3 and 4 are both 2D sql topology, where 3 is a 2D structure with large Co6 honeycomb hexagon. In complex 4, the X–H⋯π (X=C, O) interactions exist and stabilize the stack of their 2D network. In all complexes, various non-covalent interactions are found and play important roles in structure expansion and stabilization. The structural diversities are discussed. TGA and XPRD of title complexes as well as the photoluminescent properties of complexes 1 and 2 are studied in the solid state at room temperature.