Coordination polymers based on a flexible bis(triazole) ligand and aromatic polycarboxylate anions: syntheses, topological structures and photoluminescent properties

Four new coordination polymers, namely, {[Cd(btmx)(BTEC)(0.5)(H2O)]center dot H2O}(n) (1), {[Cd (btmx)(1.5)(1,2,4-HBTC)]center dot(H2O)(2)}(n) (2), {[Co(btmx)(HBTC)]center dot 2H(2)O}(n) (3) and [Co(btmx)(1,4-BDC)](n) (4) (btmx = 1,4-bis(1,2,4-triazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene, H4BTEC = 1,2,4,5-benzenetetracarboxylic acid, 1,2,4-H3BTC = 1,2,4-benzenetricarboxylic acid, 1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid and 1,4-H2BDC = 1,4-benzenedicarboxylic acid) have been obtained under hydrothermal conditions and characterized structurally. Complex 1 is a 3D 3-fold interpenetrating (4,4)-connected net with (4.6(4).8)(4(2).6(2).8(2)) topology. Complex 2 displays a 2D cabinet-like structure with infinite 1D double Cd-btmx chains. Complex 3 possesses a 3D 3-fold interpenetrating 4-connected framework with 6(6)-dia topology. Complex 4 exhibits a (4,6)-connected 3D pillar-layered structure with point symbol of (4(4).6(2))(4(4).6(10).8). The structural differences of these complexes demonstrate that the flexible ligand btmx and aromatic polycarboxylate anions play critical roles in the formation of the resulting frameworks. Furthermore, the photoluminescent properties of 1 and 2 have been studied in the solid state at room temperature.