Two Co(II) complexes, [Co(INAIP)(dib)]·4H2O and [Co(INAIP)(phen)(H2O)]·H2O have been synthesized by the reaction of 5-(isonicotinamido)isophthalic acid (H2INAIP) and CoSO4·7H2O, as well as N-donor ligands, namely 1,4-di(1-imidazolyl)benzene (dib) and 1,10-phenanthroline (phen) under hydrothermal conditions. Single-crystal X-ray diffraction analysis indicates that [Co(INAIP)(dib)]·4H2O has a two-dimensional (2D) double-layer network structure with a (4, 4) topology, while [Co(INAIP)(phen)(H2O)]·H2O displays a one-dimensional chain structure, extending to a 2D net through the π–π interactions. In addition, the photoluminescence and degradation of methyl orange in a Fenton-like process using the complexes as catalysts were investigated.

A new coordination polymer associated with cobalt ion, [Co3(Tda)3(bpp)2]·2DMF (1, Tda = thiophene-2,5-dicarboxylic acid, bpp = 1,3-bis(4-pyridyl)propane, DMF = dimethylformamide), was prepared under solvothermal conditions, and characterized by the single-crystal X-ray diffraction, element analysis, and IR spectra. Each Tda is coordinated to four CoII ions with µ4-κO:κO′:κO″,κO‴-µ2 coordination mode and each bpp ligand is ligated to two CoII ions with anti–anti bridging mode in 1. Each cobalt(II) trimer is connected to eight adjacent Co3 units via four Tda and four bpp ligands reduced to a uninodal 8-connected topology. Sorption studies conducted on this permanently microporous material imply that it can separate carbon dioxide from nitrogen and methane with high selectivity.