Polymorphism of 2D Imine Covalent Organic Frameworks
Yusen Li1, Linshuo Guo2, Yongkang Lv1
1Department of Chemistry, Institute of Molecular Plus and Tianjin Key Laboratory of Molecular Optoelectronic Science, Tianjin University, Tianjin, 300072, China.
Angewandte Chemie (International Ed. in English)
|November 27, 2020
Summary
Monomer geometry controls isomeric framework formation, with solvents fine-tuning the process. These novel frameworks show selective vitamin B12 adsorption due to unique pore structures.
Area of Science:
- Materials Science
- Supramolecular Chemistry
- Crystallography
Background:
- A2B2-type tetraphenyl benzene monomers offer a versatile platform for constructing complex porous materials.
- Controlling the isomeric structures of frameworks is crucial for tailoring their properties, such as selective adsorption.
Purpose of the Study:
- To design and synthesize para-, meta-, and ortho-substituted tetraphenyl benzene monomers (p-, m-, and o-TetPB).
- To investigate the influence of monomer geometry and reaction solvents on the formation of isomeric frameworks.
- To evaluate the selective adsorption capabilities of the synthesized frameworks for vitamin B12.
Main Methods:
- Synthesis of A2B2-type tetraphenyl benzene monomers.
- X-ray diffraction, computational simulation, and microscopy for structural characterization.
- Sorption isotherm measurements to assess adsorption properties.
Main Results:
- Both kagome (kgm) and monoclinic square (sql) framework isomers were obtained from p-TetPB and m-TetPB by varying solvents.
- Only sql frameworks were formed from o-TetPB, regardless of solvent.
- The geometry of the monomers was found to be the dominant factor in directing lattice growth.
Conclusions:
- Monomer geometry dictates framework formation, while solvents act as perturbing agents.
- The synthesized isomeric frameworks exhibit high selectivity for vitamin B12 adsorption based on pore characteristics.
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