Cu II, Co II, and Ni II complexes with R-isophthalate ( R = –CH 3 or –OCH 3) and a bent dipyridyl 2,5-bis(3-pyridyl)-1,3,4-oxadiazole: Structural diversification induced by metal ion and substituent of ligand

Abstract

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 = –CH 3 for 5-methylisophthalic acid or R = –OCH 3 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.