Synthesis, crystal structures, and properties of three helical coordination polymers with quinolinecarboxylate ligand

Abstract

Three mixed-ligand complexes [M(L)(Phen)(H₂O)] _n  · nH₂O [M =  Ni (1), Co (2), Zn (3)], (L = 2-methylquinoline-3,4-dicarboxylate dianion; phen = 1,10-phenanthroline) have been synthesized by the reaction of MCl₂ with 2-methylquinoline-3,4-dicarboxylate acid, sodium hydroxide, and 1,10-phenanthroline under hydrothermal conditions and were characterized by single-crystal X-ray diffraction. Complexes 1–3 crystallize isomorphously in the orthorhombic space group Pbca and feature 1-D helical chains. These helical chains are linked to form a 2-D layer through π–π stacking interactions, which are further linked by hydrogen bonds to form a 3-D network. Solid-state properties such as thermal stability and fluorescence emission of the polymeric Zn complex 3 have also been investigated.

Keywords:

• Crystal structure
• Coordination polymers
• Helical chains
• Fluorescent properties
• Quinolinecarboxylate acid

Acknowledgments

This work was supported by the National Natural Science Foundation of China (20761002), P.R. China, and the Natural Science Foundation of Guangxi (0832080), P.R. China.