CuII, CoII, and NiII complexes with R-isophthalate (R = -CH3 or -OCH3) and a bent dipyridyl 2,5-bis(3-pyridyl)-1,3,4-oxadiazole: Structural diversification induced by metal ion and substituent of ligand

This work presents six Cu-II, Co-II, and Ni-II supramolecular complexes assembled from a bent dipyridyl ligand 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) and R-isophthalic acids (R = -CH3 for 5-methylisophthalic acid or R= -OCH3 for 5-methoxyisophthalic acid), which have been prepared using the layer-separation diffusion method and fully characterized by IR, elemental analysis, and powder X-ray diffraction (PXRD) techniques. Single-crystal X-ray diffraction indicates that these complexes show 1-D tube-like (for Cu-II complexes 1 and 2) or discrete cage-like dinuclear (for Co-II and Ni-II complexes 3-6) coordination patterns. Furthermore, extended 3-D supramolecular architectures are constructed via secondary interactions between the coordination arrays, and three types of packing fashions are observed for the dinuclear species 3-6. Structural diversification for these complexes can be properly attributed to the inherent discrepancy of metal ions and the substituent effect of R-isophthalate tectons. (C) 2010 Elsevier B.V. All rights reserved.