Synthesis and structural characterization of 2D Zn(II), Cd(II), and Co(II) coordination polymers containing 3-chloro-1,2-benzenedicarboxylate and positional isomers of triazole-bipyridine

Abstract

Three compounds, [Zn₂L₂(4,4′-bpt)₂] _n (1), [Cd₂L₂(3,4′-bpt)(H₂O)₂] _n (2) and {[CoL(3,3′-bpt)(H₂O)]∙H₂O} _n (3) (L = 3-Cl-1,2-benzenedicarboxylate dianion, 4,4′-bpt = 1H-3,5-bs(4-pyridyl)-1,2,4-itriazole, 3,4′-bpt = 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole and 3,3′-bpt = 1H-3,5-bis(3-pyridyl)-1,2,4-triazole), based on three positionally isomeric triazole-bipyridine ligands, were synthesized. Structural analyses of 1–3 reveal diverse 2-D network structures, which are based on different [ML] _n (M = Zn, Cd, Co) chains. In the [ZnL] _n chains of 1, the carboxylic groups of L connect the adjacent Zn(II) centers with a monodentate bridging coordination mode (μ₂-η¹/ η¹ ). In 2, [CdL] _n is a double chain connected by the carboxylic groups of L with μ₃-η¹/ η²/η² and μ₃-η¹/ η¹/ η² bridges. The [CoL] _n chains of 3 are formed by the carboxylic groups of L with the μ₂-η¹/ η² coordination mode. The powder X-ray diffraction and the thermal stability of 1–3, the luminescent properties of 1 and 2, and the magnetic behavior of 3 have been briefly investigated.

Keywords:

• Positional isomeric ligands
• Crystal structures
• Luminescence properties
• Magnetic properties

Acknowledgements

We gratefully acknowledge the National Nature Science Foundation of China (Nos. 21061002, 21101035), Guangxi Natural Science Foundation of China (2010GXNSFF013001, 2012GXNSFAA053035, 2012GXNSFBA053017) and the Nature Science Foundation of Guangxi Normal University.