2015 Fiscal Year Annual Research Report
光に応答するミクロ孔を利用した異方的能動輸送膜の開発
| Project/Area Number |
15J10616
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| Research Institution | The University of Tokyo |
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Principal Investigator |
黄 虎彪 東京大学, 工学系研究科, 特別研究員(DC1)
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| Project Period (FY) |
2015-04-24 – 2018-03-31
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| Keywords | Photoresponsive / MOFs / Photo-isomerization / Polarity alteration / Photoprobe / Gas adsorption |
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| Outline of Annual Research Achievements |
In this research, photo-responsive porous coordination polymers are successfully designed and synthesized,
where azobenzene moieties are incorporated into the entire frameworks as pendants. It was found that the photo-induced isomerizations of azobenzene groups in the crystalline micropores had critical impacts on the transport of guest molecules. And the key points are summarized as follows:
(I). Azobenzene-containing ligands are synthesized and their photochemical properties are investigated by UV-vis spectra, proton NMR and etc; (II) photo-responsive porous coordination polymers are synthesized by azo ligands and metal ions. And the photo-isomerization of azobenzene groups in the frameworks is evidenced by UV-vis diffusion reflectance spectra and quantified by proton NMR technique. Under UV light irradiation, the photo-stationary state is achieved around 30 minutes later with cis-isomers fraction of 21%. And it can recover to the initial state upon visible light irradiation and heating; (III) the isomerization of azobenzene moieties inside crystalline frameworks can induce prominent polarity changes in the crystalline micropores, which is, for the first time, detected and visualized by using polarity-sensitive photoprobe, erythrosine B, as molecular probe; (IV) such prominent polarity alterations inside polyhedral pores are found to be obvious influences on the transport of guest molecules, such as polarizable carbon dioxide.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Photo-responsive moieties (azobenzene) are successfully incorporated into porous coordination polymers. And trans/cis isomerizations can be readily triggered by light or heating in the crystalline solid. According to UV reflectance diffusion spectra and proton NMR results, the cis-isomers fraction reach to 22% after achieving to the photo-stationary state upon UV light irradiation. Such isomerizations can bring about significant impact on the pore surface of crystalline nanopores, i.e. from cis-deficient less polar pores to cis-rich polar pores. The observed polarity changes in the nanopores is demonstrated to be of obvious impact on guest molecules accommodations in the porous coordination polymers. For the apolar argon gas, the diffusion rate is more than one-hundred-fold faster than than of carbon dioxide (quadrupole moment). In a word, my research target is going very well.
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| Strategy for Future Research Activity |
At present, we only tested the influence of polarity alteration on the accommodation of carbon dioxide and photoprobe. If this concept can work for some sophisticated molecules like drugs, photo-controlled release or capture of some target guest molecules is therefore, challenged in the future of my research plan, because this kind of research is of particular interests in many real applications.
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Research Products
(2 results)
