Synthesis, crystal structure and photoluminescence of a three-dimensional zinc coordination compound with NBO-type topology.

The assembly of metal-organic frameworks (MOFs) with metal ions and organic ligands is currently attracting considerable attention in crystal engineering and materials science due to their intriguing architectures and potential applications. A new three-dimensional MOF, namely poly[[diaqua(μ8 -para-terphenyl-3,3',5,5'-tetracarboxylato)dizinc(II)] dimethylformamide disolvate monohydrate], {[Zn2 (C22 H10 O8 )(H2 O)2 ]·2C3 H7 NO·H2 O}n , was synthesized by the self-assembly of Zn(NO3 )2 ·6H2 O and para-terphenyl-3,3',5,5'-tetracarboxylic acid (H4 TPTC) under solvothermal conditions. The compound was structurally characterized by FT-IR spectroscopy, elemental analysis and single-crystal X-ray diffraction analysis. Each ZnII ion is located in a square-pyramidal geometry and is coordinated by four carboxylate O atoms from four different TPTC4- ligands. Pairs of adjacent equivalent ZnII ions are bridged by four carboxylate groups, forming [Zn2 (O2 CR)4 ] (R = terphenyl) paddle-wheel units. One aqua ligand binds to each ZnII centre along the paddle-wheel axis. Each [Zn2 (O2 CR)4 ] paddle wheel is further linked to four terphenyl connectors to give a three-dimensional framework with NBO-type topology. The thermal stability and solid-state photoluminescence properties of the title compound have also been investigated.