Co-reporter:Hoan Ngoc Doan;Hayato Tsuchida;Takato Iwata;Wataru Sakai;Naoto Tsutsumi;Dai Phu Huynh
RSC Advances (2011-Present) 2017 vol. 7(Issue 53) pp:33061-33067
Publication Date(Web):2017/06/29
DOI:10.1039/C7RA03794E
Spiropyran-functionalized poly(methyl methacrylate) (PMMA) Forcespinning® fibers were fabricated using a fiber making machine of our own design, employing 1′,3′,3′-trimethyl-6-nitrospiro[1(2H)-benzopyran-2,2′-indoline] (6-nitro BIPS) as the spiropyran. The effects of the polymer solution concentration (and hence the viscosity), the spinneret rotational rate, and the internal needle diameter on the formation and morphology of the fibers were examined, using scanning electron microscopy. A rotational speed of 3000 rpm and an internal nozzle diameter of 0.35 mm (23 G) in conjunction with a polymer concentration of 15 wt% produced 6-nitro BIPS/PMMA Forcespinning fibers having a smooth morphology with no beads. The photochromic properties of the resultant fibers were characterized by reflectance spectroscopy using the Kubelka–Munk function, fluorescence excitation emission matrix (EEM) analysis, and Raman spectroscopy. The thermal decoloration dynamics of the 6-nitro BIPS in the PMMA fibers were in good agreement with the properties observed in films. These results suggest that 6-nitro BIPS and other spiropyran dyes have significant potential as probes to assess the structures of micro/nanofibers.
Co-reporter:Kenji Kinashi, Tatsuya Suzuki, Hidekazu Yasunaga, Hayato Tsuchida, Wataru Sakai, Naoto Tsutsumi, Hideki Yamane
Dyes and Pigments 2017 Volume 145(Volume 145) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.dyepig.2017.06.040
•Effects of dyeing carriers on the K/S values of PLLA fibers were investigated.•HOMO of the PLLA fibers dyed with 6-nitro BIPS exhibited −5.98 eV.•Thermodynamic properties of the 6-nitro BIPS in the fibers were determined.The effects of dyeing carriers on the color strength (K/S values) of poly(l-lactic acid) (PLLA) fibers were investigated, using the photochromic dye 1′,3′,3′-trimethyl-6-nitro-spiro(2H-1-benzopyran-2,2′-indole) (6-nitro BIPS). Both an organic solution (based on tetrachloroethylene) and an aqueous dispersion of the dye were applied to the PLLA fibers, and the resulting change in color of the PLLA samples irradiated by ultraviolet (UV) light was evaluated by spectrocolorimetry. In the case of aqueous dispersion processing, the uptake of 6-nitro BIPS on the PLLA fibers was expected to be increased when using o-phenylphenol as a carrier. The value was four times higher than that obtained using the organic solution. The energy diagrams associated with the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the 6-niro BIPS for the two dyeing processes were determined using photoelectron yield spectroscopy.Download high-res image (364KB)Download full-size image
Co-reporter:Kenji Kinashi, Yurika Miyamae, Ryotaro Nakamura, Wataru Sakai, Naoto Tsutsumi, Hideki Yamane, Gaku Hatsukano, Makoto Ozaki, Kazuya Jimbo and Takahiro Okabe
Chemical Communications 2015 vol. 51(Issue 56) pp:11170-11173
Publication Date(Web):26 May 2015
DOI:10.1039/C5CC03977K
This study attempted to visualize reversible X-ray radiation by using a poly-(L-lactic acid) (PLLA) composite fiber with an average diameter of 150 μm. The fiber contains photostimulable phosphor (PSP) BaFCl:Eu2+ particles that are subsequently dyed with the photochromic spiropyran dye (1,3,3-trimethylindolino-6′-nitrobenzopyrylospiran) (6-nitro BIPS).
Co-reporter:Kenji Kinashi, Kyun-Phyo Lee, Shinya Matsumoto, Kenji Ishida, Yasukiyo Ueda
Dyes and Pigments 2012 Volume 92(Issue 1) pp:783-788
Publication Date(Web):January 2012
DOI:10.1016/j.dyepig.2011.05.024
Bisazomethine dyes with terminal alkyl substituents of different chain lengths (BAR: R = 1, 2, 3, 4, 5 and 6) were synthesized and deposited on a glass substrate to investigate the effect of the alkyl chain length on aggregate formation. Methyl- and ethyl-substituted bisazomethine dyes (BA1 and BA2) formed J-aggregates in thin films (ca. 50 nm), whereas, propyl-, butyl-, pentyl- and hexyl-substituted derivatives (BA3, BA4, BA5 and BA6) formed H-aggregates in thin films (ca. 50 nm). The aggregate formation of the BARs changed drastically between ethyl- and propyl-substituents (BA2/BA3). However, no remarkable changes were observed in the surface morphologies of BA2 and BA3 films. It is suggested that the critical determinant of aggregate formation of BAR is the molecular packing in the film, which depends on the chain length of the terminal alkyl substituent.Highlights► Bisazomethine dyes (BAR: R = 1–6) were synthesized and investigate the effect of the alkyl chain length on the aggregate formation. ► Methyl- and ethyl-substituted BARs (BA1 and BA2) formed J-aggregates. ► Propyl-, butyl-, pentyl- and hexyl-substituted BARs (BA3, BA4, BA5 and BA6) formed H-aggregates.
Co-reporter:Kenji Kinashi;Yusuke Miyashita;Kenji Ishida;Yasukiyo Ueda
Journal of Physical Organic Chemistry 2012 Volume 25( Issue 5) pp:427-430
Publication Date(Web):
DOI:10.1002/poc.1936
A composite film containing photochromic spiropyran dye 1 and BaFCl:Eu was developed for X-ray dose measurement at a level of a few dozen gray (Gy). The reflectance intensity at selected wavelength, obtained from X-radiation, can be satisfactorily related to the absorbed dose in the range of 0−30 Gy. The composite film shows significant color change in the visible region, and the sensitivity of the composite to the absorbed dose was achieved based on the high molar extinction coefficient of the photomerocyanine form of dye 1. For practical application, the photoinduced blue area indicates an X-radiated area, and the initial pale pink area indicates an unexposed area. Copyright © 2011 John Wiley & Sons, Ltd.
Co-reporter:Kenji Kinashi;Satoshi Nakamura;Masaki Imamura;Kenji Ishida;Yasukiyo Ueda
Journal of Physical Organic Chemistry 2012 Volume 25( Issue 6) pp:462-466
Publication Date(Web):
DOI:10.1002/poc.1926
The mechanism for negative photochromism of spiropyran in silica was investigated. Prior to our study, the chemical origin of the high thermal stability of the photomerocyanine form (PMC-form) dispersed in perhydropolysilazane (PHPS), which is converted to silica at ambient temperature, had been investigated. The high thermal stability of the PMC-form is attributed to the protonated PMC-form (H⋅⋅⋅PMC-form), which is produced by intermolecular hydrogen bonding between oxide anions generated by the cleavage of the C − O bonds and the partially uncondensed Si − OH and O − H bonds of silica. Furthermore, the H⋅⋅⋅PMC-form could be thermally isomerized from the SP-form without UV light irradiation. This specific phenomenon is caused by the so-called negative photochromism. In this study, we proposed a mechanism for negative photochromism according to the relationship of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). The relationship between the HOMOs was determined using cyclic voltammetry (CV) and ultraviolet photoelectron spectroscopy (UPS). On the other hand, the relationship between the LUMOs was determined from the respective optical bandgap. As a result, the HOMO level of H⋅⋅⋅PMC-form was −6.1 eV and that of SP-form was −5.3 eV. Accordingly, the thermodynamic stabilization of H⋅⋅⋅PMC-form was attributed to the thermal isomerization through negative photochromism from the SP-form. Copyright © 2011 John Wiley & Sons, Ltd.
Co-reporter:Kenji Kinashi, Yoko Ono, Yukito Naitoh, Akira Otomo, Yasukiyo Ueda
Journal of Photochemistry and Photobiology A: Chemistry 2011 Volume 217(Issue 1) pp:35-39
Publication Date(Web):1 January 2011
DOI:10.1016/j.jphotochem.2010.09.013
The excited state dynamics of the photomerocyanine (PMC) form originating from spirobenzopyran and the bi-functional photochromic compound spirobenzopyran–azobenzene (SpAz), containing typical photochromic molecules of spirobenzopyran (Sp) and azobenzene (Az), were investigated using picosecond time-resolved fluorescence measurements in solution at 200 and 285 K and in a PMMA polymer film at 298 K. While the fluorescence lifetimes of PMC were about twice as long as those of SpAz under all experimental conditions, both lifetimes showed similar strong dependence on viscosity rather than temperature. These results suggest that non-radiative decay to an intermediate state could be accompanied by a significant conformational change. The effect of the Az moiety in this relaxation process is also discussed. It is unlikely that an energy transfer from the PMC moiety to the Az moiety occurs. It was concluded that the PMC moiety in the bi-functional SpAz is independent from the Az moiety.
Co-reporter:Kenji Kinashi, Yurika Miyamae, Ryotaro Nakamura, Wataru Sakai, Naoto Tsutsumi, Hideki Yamane, Gaku Hatsukano, Makoto Ozaki, Kazuya Jimbo and Takahiro Okabe
Chemical Communications 2015 - vol. 51(Issue 56) pp:NaN11173-11173
Publication Date(Web):2015/05/26
DOI:10.1039/C5CC03977K
This study attempted to visualize reversible X-ray radiation by using a poly-(L-lactic acid) (PLLA) composite fiber with an average diameter of 150 μm. The fiber contains photostimulable phosphor (PSP) BaFCl:Eu2+ particles that are subsequently dyed with the photochromic spiropyran dye (1,3,3-trimethylindolino-6′-nitrobenzopyrylospiran) (6-nitro BIPS).
![[4-(piperidin-1-yl)benzylidene]propanedinitrile](http://img.cochemist.com/ccimg/66900/66883-91-8.png)
![[4-(piperidin-1-yl)benzylidene]propanedinitrile](http://img.cochemist.com/ccimg/66900/66883-91-8_b.png)
![Propanedinitrile, [[4-(hexahydro-1H-azepin-1-yl)phenyl]methylene]-](http://img.cochemist.com/ccimg/199300/199297-13-7.png)
![Propanedinitrile, [[4-(hexahydro-1H-azepin-1-yl)phenyl]methylene]-](http://img.cochemist.com/ccimg/199300/199297-13-7_b.png)