Two sinusoidal wavelike 2D coordination polymers with benzophenone-4,4′-dicarboxylate

Two isomorphic 2D metal–organic coordination polymers, [Zn(bpndc)(H2O)]∞ (1) and [Cd(bpndc)(H2O)]∞ (2), have been hydrothermally prepared by exploring a semi-rigid V-type dicarboxylate ligand, benzophenone-4,4′-dicarboxylic acid (H2bpndc). Two complexes were characterized by single crystal X-ray diffraction, elemental analyses, IR spectrum, powder X-ray diffraction, thermal analyses, UV–Vis and fluorescence emission spectra. The metal ions in 1 and 2 are connected by carboxylate groups of bpndc to generate a 1D chain with doubly helical structures. The chains are linked by bpndc to form a 2D sinusoidal wavelike layer, which are further assembled with O–H⋯O hydrogen bonds to generate a 3D supramoleclar networks. The topology of 2D structure is an unusual flat (3,4)-connected net forming 4 and 6-gons with the Schläfli notation of (4·62)(42·62) (see Natarajan and Mahata, 2009 [14]).