Synthesis, structure, and thermal properties of two honeycombs like three-dimensional complexes composed by cobalt salt and asymmetric ligand

Two new coordination polymers {[Co2(BTC)(OH)(H2O)2] 2 · 2H2O}n (1) (BTC = 1,2,4-benzenetricarboxylate) and {Co2(NA)4(H2O)}n (2) (NA = nicotinate) had been synthesized under the hydrothermal condition and characterized by elemental analyses, IR, and the single crystal X-ray diffraction. Complexes 1 is a new three-dimensional network composed by tetranuclear Co cluster. It can be seen constructed by two-dimensional Co–O inorganic layers supported by BTC ligands. Complex 2 is also a three-dimensional network. To our surprise, Complex 1 and 2 both contain honeycomb-like structure surrounded by Co clusters and BTC, NA ligands. We think it is difficult to construct such structures with asymmetry ligand such as BTC and NA. Furthermore, the thermal stability properties of the two complexes are studied.