Solvothermal Synthesis and Structural Characterisation of Metal-Organic Frameworks with Paddle-Wheel Zinc Carboxylate Clusters and Mixed Ligands

A series of 3D interpenetrating metal-organic frameworks, namely, [Zn-3(BPDC)(3)(4-BPT)(1.5)]center dot 1.5DMF [1, BPDC = biphenyl-4,4'-dicarboxylic acid, 4-BPT = 4-amino-3,5-bis(4-pyridyl)1,2,4-triazole, DMF = dimethylformamide], [Zn-3(BPDC)(3)(4-PYTZ)(1.5)]center dot 1.5DMF [2, 4-PYTZ = 3,6-bis(pyridin-4-yl)-1,2,4,5-tetrazine], [Zn-2(OBA)(2)(4-PYTZ)]center dot 2DMF [3, OBA = 4,4'-oxybis(benzoate)], [Zn-2(OBA)(2)(3-PYTZ)center dot Zn-2(OBA)(2)(DMF)(2)]center dot 7DMF [4, 3-PYTZ = 3,6-bis(pyridin-3-yl)-1,2,4,5-tetrazine] and [Zn-2(OBA)(2)(3-BPT)]center dot 2.5DMF [5, 3-BPT = 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole] were synthesized by the reaction of Zn(NO3)(2)center dot 6H(2)O with various dipyridyl derivatives and rigid or nonrigid aromatic dicarboxylate ligands. These five compounds were constructed by paddle-wheel-type coordination of Zn-II pairs and mixed ligands, which can be simplified as nodes and linkers to generate a variety of topologies. Compounds 1 and 2 exhibit threefold interpenetrated 6-connected pcu topology. The interpenetration observed in compounds 1 and 2 is a rare case of heterointerpenetration. The structure of 3 is derived from a 2D double interpenetrated rhombic grid substructure, and is an interesting example of a self-catenated framework displaying a 6-connected uninodal framework with a point symbol (4(4).6(10).8). Compound 4, which is derived from a crosslinked threefold interpenetrated substructure with pts topology, displays a self-catenated 4,6-connected binodal framework with the point symbol (4(2).6(2).7(2)) (4(2).6(8).7.8(4)). Compound 5 exhibits a self-catenated 6-connected structure with rob topology, and with the point symbol (4(8).6(6).8). Compounds 1-5 also display varied luminescence properties in the solid state.