Solvent or Temperature Induced Diverse Coordination Polymers of Silver(I) Sulfate and Bipyrazole Systems: Syntheses, Crystal Structures, Luminescence, and Sorption Properties

Three new coordination polymers, [Ag-4(H(2)bpz)(4)(SO4)(2)]center dot H2O (1), [Ag-2(H(2)bpz)(2)(SO4)]center dot 3H(2)O (2), and [Ag-3(H(2)bpz)(4)](SO4)(2/3)(OH)(5/3)center dot 4H(2)O (3) have been solvothermally synthesized with Ag2SO4 and flexible ligand 3,3',5,5'-tetramethyl-4,4'-bipyrazole (H(2)bpz) in different solvents and temperatures. Complex 1 is a 2-fold interpenetrated three-dimensional (3D). framework with an uncommon (3,5)-connected hms topology. Complex 2 is a structural isomer of 1 and shows a three-connected 2D ths net consisting of interesting 3-fold and 2-fold heterochiral helical chains. Complex 3 discloses a grid layer structure, containing heterochiral helical chains and an unusual meso-helix. More interestingly, three sets of layers in 3 stack in different directions, affording an unprecedented 2D + 2D + 2D -> 3D polycatenating cationic framework with ID + 3D porous systems. In 1-3, H(2)bpz exhibit exobidentate bridging fashions with wide-ranged interpyrazole tilting angles and changeable coordination configurations, such as cis and trans fashions in 1 and 3 and uniform trans fashion in 2. These lead to the isomeric [Ag(H(2)bpz)](n) arrays of wavelike and helical chains in 1 and 2, respectively. Complexes 1-3 display solid-state photoluminescence stemming from the ligand-centered fluorescent emissions of H(2)bpz. Because of the highly polar framework, 3 shows excellent adsorption selectivity for CO2 over N-2.