Syntheses, Structures, and Properties of Two Zinc(II) Metal-Organic Frameworks based on Biphenyl-2,3,3′,5′-tetracarboxylic Acid and N-Donor Ancillary Ligands

Hydrothermal reactions of biphenyl-2,3,3',5'-tetracarboxylic acid (H(4)bptc) with zinc salts in the presence of 1,4-bis(2-pyridylmethyl) piperazin (bpmp) and 4,4-dipyridyl (dpy) afforded the coordination polymers {[Zn-2(bptc)(bpmp)]center dot 3H(2)O}(n) (1) and {[Zn(H(2)bptc)(dpy)]center dot 3H(2)O}(n) (2). Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectroscopy, and TG analyses. Complex 1 displays an unusual three-dimensional (3D) supramolecular motif generated by hydrogen bonding interactions between two single-layered 2D networks. Complex 2 represents a 2D layer structure, and such layers are further united together into three-dimensional supramolecular structure through intricate hydrogen bonding. In addition, luminescence properties of complexes 1 and 2 were also investigated.