Synthesis, characterization, and magnetic properties of two new Co(II) coordination polymers with a carboxylate- and benzimidazolylcontaining ligand

摘要

The hydrothermal reaction of cobalt(II) nitrate hexahydrate with 5-(benzimidazol-1- ylmethyl)isophthalic acid (H_2L) leads to the formation of a complex [Co(L)] (1). In the presence of 2-(pyridin-2-yl)-1H- benzimidazole (pybim) as an auxiliary ligand, a complex [Co(L)(pybim)] ·H_2O (2) was obtained. The complexes 1 and 2 have been characterized by single-crystal and powder X-ray diffraction, IR spectroscopy, and elemental and thermogravimetric analyses. Complex 1 shows a binodal (3,6)-connected 2D kgd network with (4~3)_2 (4 ~6.6~6.8~3) topology; 2 shows a chain structure, further linked together by hydrogen bonding and π- π interactions to give rise to a 3D supramolecular framework. Complexes 1 and 2 are examples of auxiliary ligand-assisted structural diversity. The frameworks of 1 and 2 display high thermal stability up to 400°C. The magnetic properties of 1 were investigated.