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Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks (MOFs)
Published on: January 17, 2020
Polymorphism in homochiral zinc phosphonates.
Xun-Gao Liu1, Song-Song Bao, Yi-Zhi Li
1State Key Laboratory of Coordination Chemistry, Coordination Chemistry Institute, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People's Republic of China.
Inorganic Chemistry
|June 14, 2008
Summary
This study reports four homochiral zinc phosphonates, including enantiomers and polymorphic phases. These compounds exhibit unique crystal structures influenced by temperature and guest molecules.
Area of Science:
- Coordination Chemistry
- Materials Science
- Crystallography
Background:
- Homochiral metal-organic frameworks are crucial for enantioselective catalysis and chiral separations.
- Understanding the factors influencing the formation of specific crystal structures and polymorphs is essential for materials design.
Purpose of the Study:
- To synthesize and characterize four novel homochiral zinc phosphonates.
- To investigate the structural differences between enantiomers and polymorphic phases.
- To explore the impact of temperature and guest molecules on polymorphism.
Main Methods:
- Single-crystal X-ray diffraction to determine crystal structures.
- Chiral synthesis techniques to obtain enantiomerically pure compounds.
- Variable-temperature studies and guest molecule inclusion experiments.
Main Results:
- Four homochiral zinc phosphonates, denoted as alpha-(S)-[Zn 2(pemp)(pempH)Cl] (1), alpha-(R)-[Zn 2(pemp)(pempH)Cl] (2), beta-(S)-[Zn 2(pemp)(pempH)Cl] (3), and beta-(R)-[Zn 2(pemp)(pempH)Cl] (4), were successfully synthesized and characterized.
- Compounds 1 and 2 are enantiomers, crystallizing in the orthorhombic P2(1)2(1)2(1) space group.
- Compounds 3 and 4 represent polymorphic phases of 1 and 2, respectively, crystallizing in the monoclinic P2(1) space group.
- Polymorphism was observed to be induced by temperature variations or the presence of additional organic molecules.
Conclusions:
- The study successfully synthesized and structurally characterized four homochiral zinc phosphonates.
- Enantiomeric pairs and distinct polymorphic forms were identified, highlighting structural diversity.
- Temperature and guest molecules were confirmed as key factors in inducing polymorphism in these zinc phosphonate systems.
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