Microporous 3-D chiral metal-organic framework with a quartzlike topology based on an achiral building unit

Abstract

A zinc coordination polymer, Zn(IN)₂ · 2H₂O (1) (HIN = isonicotinic acid), has been synthesized and characterized by IR, elemental analysis, thermogravimetric analysis, and single crystal X-ray diffraction. This compound crystallizes in the chiral space group P6₂ with a = 15.512(3), b = 15.512(3), c = 6.262(2) Å, V = 1304.9(5) ų, and Z = 3. The O and N atoms of the IN ligand are coordinated to a Zn^II ion, locking the asymmetry of the IN ligand and transferring this asymmetry throughout the crystal structure to “direct” the formation of a chiral network. The structure of 1 is characteristic of a 3-D quartz-like framework, which contains hetero-chiral helical channels (pseudo-trigonal and hexagon channels) alternately along the c-axis. Compound 1 exhibits high stability and intense fluorescent emission at room temperature.

Keywords:

• Zinc(II) compound
• Crystal structures
• Interpenetration
• Topology
• Chirality

Acknowledgments

This project is supported by the National Natural Science Foundation of China (20773104), the Program for New Century Excellent Talents in University (NCET-06-0891), the Key Project of Chinese Ministry of Education (810243), the Key Project of Key Laboratory of Shaanxi Province (08JZ81), the Natural Science Foundation of Hubei Provinces of China (2009H09), the Natural Scientific Research Foundation of Shaanxi Provincial Education Office of China (08JK311), and the Scientific Research Foundation of Shaanxi Provincial Education Office of China (08JK490).