Two metal-carboxylate-azide coordination networks derived from 1,4-bis(3-carboxylatopyridinium-1-methylene)benzene: Synthesis, structure and properties

Betaine-type ligands are an attractive class of zwitterionic molecule, which have attracted considerable interest because they may not only keep the versatile coordination modes of carboxylate groups but also provide a new way to adjust the charge distribution of coordination polymers by cationic pyridinium groups. In this article, two coordination polymers composed of betaine-type ligand and azide anions, {[Co-2(L)(N-3)(4)]n center dot 2H(2)O}(n) (1), [Zn(L)(N-3)(2)](n) (2) (H2L center dot 2Cl= 1,4-bis(3-carboxylatopyridinium-1-methylene)benzene dichloride), have been synthesized. These compounds were characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis and single-crystal X-ray diffraction. The X-ray diffraction crystal structure analysis reveals that the complex 1 is a twofold interpenetrating three-dimensional framework. The magnetic measure shows that complex 1 exhibits a ferromagnetic behavior at low temperature. Complex 2 displays a one-dimensional chain, which is further extended into a 3D framework through hydrogen bond and van der Waals interactions. The luminescence data of complex 2 shows the emission of a yellow luminescence. Remarkably, complexes 1 and 2 both exhibit a good photocatalytic activity for degradation of rhodamine B (RhB) under the simulated sunlight irradiation.