| 研究実績の概要 |
We have been working on the project about catenane-based responsive metal-organic frameworks (MOFs). Catenanes have been widely studied in solution as an individual molecule. Their dynamic properties are particularly interesting as they can lead to the potential application as molecular switches. We are keen to understand how the mechanical bond of catenane can bring dynamic properties to the usually rigid solid-state material: MOFs.
The synthesis of suitable ligand has been a challenge. In many reactions, catenanes are formed in competition with other macrocycles and oligomers. As a result, the yield of desired catenane product is low. The synthesis has been performed many times during several months in order to obtain enough ligand.
The reaction between the ligand and metal ions such as zinc (II) resulted in a three-dimensional metal-organic framework which has been successfully characterized by single-crystal X-ray crystallography after several months’ trial. The synthetic method of MOF was optimized in order to obtain crystals with good enough quality for X-ray diffraction. The crystal was found to be sensitive to solvent loss, which took us a long time to learn how to handle it properly. The MOF showed temperature-dependent polymorphism, as observed through single-crystal X-ray crystallography. The dynamic property of the MOF was also characterized by powder X-ray diffraction and gas sorption.
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