Syntheses, crystal structures, and optical properties of a series of transition metal coordination polymers with chelidamic acid and 4,4′-bipyridine

Abstract

A series of transition metal (Zn, Cu, Mn) complexes with chelidamic acid (2,6-dicarboxy-4-hydroxypyridine, H₃CAM) and 4,4′-bipyridine (bipy), [Zn₂(bipy)Cl₂] _n (1), {[Zn₂(HCAM)(H₂CAM)₂] · (bipy) · 3.5H₂O} _n (2), [Mn₃(HCAM)₃(H₂O)₇] · (bipy) · 3H₂O (3), [Mn₂(HCAM)₂(bipy) · (H₂O)₂] · 4H₂O (4), [Cu₂(HCAM)₂(bipy) · (H₂O)₂] · 4H₂O (5), and Cu₂(HCAM)₂(bipy) · (H₂O)₂ (6), have been synthesized by hydrothermal or solution methods and characterized by single-crystal X-ray diffraction. The structural analyses reveal that 1 exhibits a zigzag chain of Zn(II), Cl⁻, and 4,4′-bipyridine. In 2, a 1-D polymeric [Zn₂(HCAM)(H₂CAM)₂] _n chain and a discrete 4,4′-bipyridine assemble into a 2-D supramolecular network via H-bonds. Complex 3 consists of asymmetric units of Mn₃(HCAM)₃(H₂O)₇ that are linked by hydrogen bonds to form a 2-D H-bonded network. Complexes 4–6 are isomorphous and possess discrete structures. The photoluminescent properties of 1–6 at room temperature were studied.

Keywords:

• Crystal structures
• Coordination polymers
• Photoluminescent properties
• Chelidamic acid
• 4,4′-Bipyridine

Acknowledgments

We gratefully acknowledge the financial support of the NSF of China (20801026), the NSF of Jiangxi Province (20114BAB203005), the Aviation Science Foundation of China (2008ZF56012), Science Foundation of State Key Laboratory of Structural Chemistry (20100015), and Open Fund of the Key Laboratory of Nondestructive Testing, Ministry of Education, Nanchang Hangkong University (ZD200929007).