Assembly of a series of coordination polymers built from rigid a tetracarboxylate ligand and flexible bis(imidazole) linker: syntheses, structural diversities, luminescence sensing, and photocatalytic properties.

Hydrothermal reactions of aromatic terphenyl-4,2'',5'',4'-tetracarboxylic acid (Htta) and transitional metal cations in the presence of two flexible N-donor ancillary ligands afforded four novel coordination polymers, namely, {[Zn(tta)(m-bimb)]·HO} (1), [Ni(tta)(m-bimb)(HO)] (2), [Ni(Htta)(o-bimb)·HO] (3), and [Cd(tta)(o-bimb)] (4), from solvothermal reactions in the presence of bis(imidazole) bridging linkers (m-bimb = 1,3-bis(imidazol-1-ylmethyl)benzene, and o-bimb = 1,2-bis(imidazol-1-ylmethyl)benzene). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses (EA), powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. Compound 1 displayed a 2-fold 3D → 3D parallel entangled (4,4)-connected bbf net with the point symbol of (6·8)(6). Compound 2 featured a predocumented 3D (4,8)-connected (3·5·6)(3·4·5·6) net. Compound 3 exhibited a 2D 4-connected sql sheet with the point symbol of (4·6), and compound 4 showed a 2D 4-connected (3·6·7) kgm sheet. To our delight, fluorescence measurements showed that compound 1 could selectively and sensitively detect Cr cations and nitrobenzene derivatives (nitrobenzene (NB), p-nitrotoluene (PNT), and p-nitroaniline (PNA)), which suggested that CPs of 1 was a promising bifunctional luminescence sensor material that could sense metal ions and small organic molecules. Moreover, 1 showed excellent photocatalytic activity.