4,4′-Bipyridine-aided synthesis and characterization of Zn(II) and Cd(II) 2-sulfoterephthalate complexes

•Complexes 1–3 possess helices with different chirality arranging alternately.•The structural diversity can be attributed to various coordination modes of ligands.•The formation of helical structure is related to the adjacent carboxyl and sulfonate groups.•Bpy exhibits three roles: bridge, hydrogen bonding acceptor, and template.

Six d10 complexes, [Zn1.5(stp)(bpy)0.5(H2O)2]·0.5H2O (1), Cd1.5(stp)(bpy)0.5(H2O)2 (2), [Cd1.5(stp)(bpy)(H2O)]·H2O (3), [Zn0.5(bpy)0.5(H2O)2][Zn(stp)(bpy)(H2O)]·0.5H2O (4), Cd3(stp)2(bpy)3(H2O)3 (5), Hbpy·[Zn0.5(bpy)(H2O)2][Zn0.5(stp)(H2O)]·H2O (6) based on 2-sulfoterephthalate (stp3−) and 4,4′-bipyridine (bpy) have been synthesized under hydro/solvo-thermal conditions and structurally characterized. Complex 1 exhibits a three-fold interpenetrated 3D porous architecture. Complexes 2 and 3 possess helices with different chirality arranging alternately. 4 and 6 are addition compounds, which compose of complex cation and complex anion. Complex 5 features a 3D layer-pillar framework in which a (4, 4) grid layer is constructed by stp3− ligands and Cd(II) ions, and the layers are further connected by bpy pillars. The solid-state luminescent properties of the coordination polymers have also been investigated.

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