Synthesis, structures and physical properties of mixed-ligand coordination polymers based on a V-shaped dicarboxylic ligand

Four coordination polymers formulated as [Ni-2(hfipbb)(2)(2,2'-bipy)(2)(H2O)(4)] (1), [Ni(4,4'-bipy)(hfipbb)(H2O)]center dot 0.5DMF (2), [Ni-2(hfipbb)(2)(BPE)(1.5)(H2O)(mu(2)-H2O)]center dot DMF center dot 2H(2)O (3) and Zn(.hfipbb)(2,2'-bipy)center dot 0.5DMF (4) (H-2 hfipbb = 4,4'-(hexafluoroisopropylidene)bis(benzoic acid); 2,2'-bipy = 2,2'-bipyridine; 4,4'-bipy = 4,4-bipyridine; BPE = 1,2-di(4-pyridyl)ethane; DMF = N, N-dimethylformamide) have been synthesized under solvothermal conditions based on the V-shaped H(2)hfipbb ligand and different auxiliary linear N-containing ligands. Compound 1 exhibits a three dimensional ( 3D) supramolecular network built from 0D rings linked through hydrogen bonds and pi-pi packing interactions. Compound 2 displays a 3D 3-fold interpenetrating diamond network with a point symbol of (6(6)). Compound 3 gives a double layer structure with (4(4).6(2))-sql topology built from {Ni-2} clusters bridged by BPE and hfipbb(2)-ligands. Compound 4 is a 3D array formed by interdigitated 1D zigzag [Zn-2(hfipbb)(2)](n) ribbons, in which the Zn-2(COO)(4) paddle-wheel SBUs are linked by two hfipbb(2)-ligands. Compounds 2-4 exhibit hydrophobic properties which may have potential applications in hydrophobic materials. The temperature-dependent magnetic susceptibility study shows that compound 3 exhibits antiferromagnetism properties. The photoluminescence of 4 was studied in the solid state at room temperature, and it shows broad emission with a maximum peak at around 385 nm upon excitation at 335 nm.