Ammonium Derivative

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Volker Grunewald - One of the best experts on this subject based on the ideXlab platform.

Kai Hofner - One of the best experts on this subject based on the ideXlab platform.

Fuyuki Ito - One of the best experts on this subject based on the ideXlab platform.

  • fluorescence properties of nanoaggregates of pyrene Ammonium Derivative and its photoinduced dissolution and reaction in tetrahydrofuran aqueous solutions
    Research on Chemical Intermediates, 2015
    Co-Authors: Fuyuki Ito, Takehiro Sagawa, Hirotaka Koshiyama
    Abstract:

    We studied the fluorescence properties of nanoaggregates of pyrene Ammonium Derivative (PyAm) and their photoinduced dissolution and reaction in tetrahydrofuran (THF)/aqueous solution. The final concentration (dye concentration after reprecipitation) dependence of the fluorescence peak was measured. The fluorescence peak of PyAm that originated from the excimer is shifted to the long wavelength side increasing with the final concentration, which is ascribable to the characteristic fluorescence spectral changes depending on their size. The size-dependent fluorescence change in the nanoaggregates is related to some molecular conformation, packing, and elastic properties of the nanoparticles at the surface. To understand the fluorescence properties of the intermediates from aggregates to crystals is important for the studies of organic nanocrystals/aggregates prepared by the reprecipitation methods. We also determined the fluorescence spectra of the PyAm nanoaggregates in a THF/aqueous solution by photoinduced dissolution and reaction. It originated from the photochemical reaction between PyAm and THF. Changes in the perpendicular light scattering intensity by photoirradiation supports the photoinduced dissolution of PyAm in the THF/aqueous solution. These findings are important in the research field of photochemical reactions in organic nanocrystals.

  • Properties and evolution of emission in molecular aggregates of a perylene Ammonium Derivative in polymer matrices.
    Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology, 2015
    Co-Authors: Fuyuki Ito, Yuri Ugachi, Hirofumi Sato, Narumi Oka, Syoji Ito, Hiroshi Miyasaka
    Abstract:

    Size-dependent fluorescent properties of aggregates of a perylene Ammonium Derivative (PeryAm) were studied by steady-state and time-resolved spectroscopic methods. Quantitative analyses of aggregated states in aqueous solution indicated that the aggregation proceeded through dimer units of PeryAm. The fluorescence of the aggregate in the PVA film prepared from the aqueous solution continuously redshifted with an increase in the concentration of PeryAm in the mother liquor while keeping the absorption spectra in almost the same band shapes. Fluorescence anisotropy values of aggregates in the PVA film were dependent on the monitoring wavelength, and time profiles of the fluorescence at longer wavelengths showed a rapid increase just after the pulsed excitation. These results indicated efficient energy transfer to the stable sites in aggregates. Fluorescence microscopy images showed that aggregates were segregated in the PVA film and the color of the emission was dependent on the size of the aggregate. Under the steady-state irradiation, the emission color of the aggregates changed from green to yellow, which was attributable to the association of a small cluster of PeryAm with the green emission resulting in the formation of yellow-colored aggregates. On the basis of these results, we have discussed the mechanisms and dynamics of the aggregation and size-dependent emission in aggregates.

  • Fluorescence properties of nanoaggregates of pyrene Ammonium Derivative and its photoinduced dissolution and reaction in tetrahydrofuran/aqueous solutions
    Research on Chemical Intermediates, 2014
    Co-Authors: Fuyuki Ito, Takehiro Sagawa, Hirotaka Koshiyama
    Abstract:

    We studied the fluorescence properties of nanoaggregates of pyrene Ammonium Derivative (PyAm) and their photoinduced dissolution and reaction in tetrahydrofuran (THF)/aqueous solution. The final concentration (dye concentration after reprecipitation) dependence of the fluorescence peak was measured. The fluorescence peak of PyAm that originated from the excimer is shifted to the long wavelength side increasing with the final concentration, which is ascribable to the characteristic fluorescence spectral changes depending on their size. The size-dependent fluorescence change in the nanoaggregates is related to some molecular conformation, packing, and elastic properties of the nanoparticles at the surface. To understand the fluorescence properties of the intermediates from aggregates to crystals is important for the studies of organic nanocrystals/aggregates prepared by the reprecipitation methods. We also determined the fluorescence spectra of the PyAm nanoaggregates in a THF/aqueous solution by photoinduced dissolution and reaction. It originated from the photochemical reaction between PyAm and THF. Changes in the perpendicular light scattering intensity by photoirradiation supports the photoinduced dissolution of PyAm in the THF/aqueous solution. These findings are important in the research field of photochemical reactions in organic nanocrystals.

  • Concentration-dependent Fluorescence Properties of a Water-soluble Perylene Ammonium Derivative in Solutions and Polymer Matrices
    Chemistry Letters, 2012
    Co-Authors: Fuyuki Ito, Yuri Ugachi, Tomoko Sasaki
    Abstract:

    A water-soluble perylene Ammonium Derivative was synthesized and its fluorescence spectra in solution and in polymer matrices were measured as a function of concentration. The concentration-depende...

Mathias Oelke - One of the best experts on this subject based on the ideXlab platform.

Stefan Machtens - One of the best experts on this subject based on the ideXlab platform.