- Synthesis of spiropyran with methacrylate at the benzopyran moiety and control of the water repellency and cell adhesion of its polymer film
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Stimuli-responsive materials have been actively researched over the past few decades. Among such materials, spiropyran is one of the most attractive compounds because the structure and polarity of the material are dramatically changed after photo irradiation, unlike other materials. In this work, we designed and synthesized a spiropyran derivative (SpMA) with a methacryloyl group on the nitrobenzene ring of a spiropyran skeleton. The UV spectra of the newly synthesized SpMA showed the photo-isomerization of spiropyran. The maximum absorption wavelength (λmax) of SpMA was 616 nm in n-hexane, a nonpolar solvent, although λmax of SpMA was 532 nm in methanol, a polar protic solvent, which resulted in an 84 nm blue-shift. SpMA was successfully polymerized by ruthenium (Ru)-catalyzed living radical polymerization. Poly(SpMA) (PSpMA) was then spin-coated on a PET substrate in order to control the surface properties of water repellency and cell adhesion. The water repellency was decreased approximately 10° under UV irradiation, because of the polarity change of PSpMA caused by photo-isomerization from the spiropyran (SP) type to the merocyanine (MC) type. In addition, NIH3T3 cells were spread only on 6% of the surface of the PSpMA thin film after UV irradiation compared with no UV irradiation. The polarity change of PSpMA by photo-isomerization is also believed to be the reason for this behavior. As a result, we successfully synthesized a photo-controllable cell culture scaffold.
- Ajiro, Hiroharu,Ando, Tsuyoshi,Murase, Nobuo
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p. 1489 - 1495
(2020/03/06)
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- Crystal and solution structures of photochromic spirobenzothiopyran. First full characterization of the meta-stable colored species
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Full elucidation for stable, colorless, and meta-stable colored structures of a new spirobenzothiopyran has been achieved both in the solid state and in a solution. 1′,3′,3′-Trimethyl-6-nitrospiro[(2H)-1-benzothiopyran-2, 2′-indoline] with an ester group as a substituent at the 8-position of 1-sp shows photochromism. The blue-green colored species resulted from UV irradiation (365 nm) in one minute and spontaneously bleaches within one minute in acetone and methanol at 27 °C. UV exposure (365 nm) of 1-sp in methanol for 3 h at room temperature results in the growth of deep blue needlelike single crystals of the open form of spirobenzothiopyran, photomerocyanine 1-pmc, whose structures in the solid state and in solution were obtained unambiguously. The X-ray structural analysis of 1-pmc revealed the molecular structure of the zwitterionic photomerocyanine with s-trans,s-trans conformation. 1-pmc is soluble to polar solvents and thermally returns to 1-sp. In the DMSO solution, 1-pmc is found to return slowly to 1-sp (1-pmc gave only 18% of 1-sp for 30 min at 22 °C). The detailed NMR studies in DMSO-d6 including COSY and NOE techniques as well as isotope labeling of the compound showed the structure with s-trans,s-cis conformation in a solution.
- Hirano, Masafumi,Osakada, Kohtaro,Nohira, Hiroyuki,Miyashita, Akira
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p. 533 - 540
(2007/10/03)
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- Synthesis and Photochemical Properties of Novel Spirobenzoselenazolinobenzopyrans
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5-Methoxy-3-methyl-6'-nitrospirobenzoselenazolinobenzopyrans have been newly prepared and their reversible structure changes induced by light were characterized by spectroscopic studies.Their stable colored-forms were identified as 5-methoxy-3-methylbenzoselenazolenium-2-trans-(5'-nitrostyryl-2'-oxide) being a zwitterionic structure.
- Hirano, Masafumi,Miyashita, Akira,Shitara, Hiroaki,Nohira, Hiroyuki
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p. 1873 - 1876
(2007/10/02)
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- Synthesis and Metastable Structure of New Photochromic Spiroindolinobenzothiopyrans
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Photochromic spiroindolinobenzothiopyrans having a methacryloxymethyl group have been prepared and their colored forms were demonstrated to be a zwitterionic structure on the basis of the spectroscopic data.
- Hirano, Masafumi,Miyashita, Akira,Nohira, Hiroyuki
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p. 209 - 212
(2007/10/02)
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