Author
Tatsuya Morozumi
Bio: Tatsuya Morozumi is an academic researcher from Hokkaido University. The author has contributed to research in topics: Fluorescence & Anthracene. The author has an hindex of 10, co-authored 29 publications receiving 477 citations.
Topics: Fluorescence, Anthracene, Intramolecular force, Rotaxane, Moiety
Papers
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TL;DR: In this article, 2,2,3, and 5 pyrenes at both terminals of polyoxyethylene compounds were synthesized, and their complexation behavior with alkaline earth cations was investigated by fluorescence spectrometry, fluorescence lifetimes, and 1H NMR spectrometric.
Abstract: New fluorescent reagents, 2,2‘-[oxybis(3-oxapentamethyleneoxy)]-bis[N-(1-pyrenylmethyl)benzamide)] (4) and its analogues (2, 3, and 5) which have two pyrenes at the both terminals of polyoxyethylene compounds, were synthesized, and their complexation behavior with alkaline earth cations was investigated by fluorescence spectrometry, fluorescence lifetimes, and 1H NMR spectrometry. These reagents (3−5) showed strong intramolecular excimer emissions around at 480 nm in the fluorescence spectra. On the complexation with alkaline earth metal cations, the increase of monomer emission around at 400 nm accompanied by the disappearance of intramolecular excimer emission of free reagents was observed. These reagents formed a 1:1 complex, and the order of complex formation constants was Ca2+ ≅ Sr2+ > Ba2+ > Mg2+ > Li+ for all reagents. 1H NMR spectra of these complexes with alkaline earth cations suggested the helical structures of the complexes. Fluorescence spectral changes at the formation of complexes depended ...
101 citations
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TL;DR: New fluorophores based on linear polyether N,N‘-[oxybis(3-oxapentamethylenoxy)-2-phenyl]bis(9-anthracenecarbonamide) (3) and its analogues (2 and 4) have been synthesized, and their complexation pr...
Abstract: New fluorophores based on linear polyether N,N‘-[oxybis(3-oxapentamethylenoxy)-2-phenyl]bis(9-anthracenecarbonamide) (3) and its analogues (2 and 4) have been synthesized, and their complexation pr...
76 citations
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TL;DR: Novel fluorescent reagents 1 and 2 were synthesized and in the absence of metal ions, the fluorescence emissions were quite weak, but their intensities were much greater in the presence of alkaline earth metal ions.
60 citations
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TL;DR: In this article, a new fluorescent ionophore for Mg2+, 4′-(1-naphthaleneacetamido)benzo-15-crown-5 (1), was synthesized, and its complexation behavior in acetonitrile was investigated by means of UV and fluorescence spectrometry.
51 citations
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TL;DR: In this paper, the effects of complexed metal ions on trans−cis photoisomerization reactions of two azobenzene compounds having a crown ether ring, 1a (small ring) and 1b (large ring) were investigated.
Abstract: The effects of complexed metal ions on trans−cis photoisomerization reactions of two azobenzene compounds having a crown ether ring, 1a (small ring) and 1b (large ring) were investigated. The photoisomerization of 2,2‘-dimethoxyazobenzene (2) was compared as a control. Anomalous increase in the quantum yields of the photoisomerization of 1a and 1b were observed by complexation with alkaline earth metal ions in both cases of photo irradiation at n→π* and π→π* absorption bands, except for some cases. These increase was attributed to the interaction between coordinated metal ions and oxygen atoms on 2,2‘-position and/or nitrogen atoms of the azobenzene moiety. The dependence of the quantum yields on the ring size of the crown ether was also discussed.
45 citations
Cited by
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TL;DR: The main classes of fluorescent molecular sensors for cation recognition are presented: they differ by the nature of the cation-controlled photoinduced processes: photoinduced electron transfer, photoinduced charge transfer, excimer formation or disappearance as discussed by the authors.
2,128 citations
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TL;DR: This critical review details the studies completed to date on the 3 main classes of azobenzene derivatives and explains the mechanism behind the isomerization mechanism.
Abstract: Azobenzene undergoes trans → cisisomerization when irradiated with light tuned to an appropriate wavelength. The reverse cis →transisomerization can be driven by light or occurs thermally in the dark. Azobenzene's photochromatic properties make it an ideal component of numerous molecular devices and functional materials. Despite the abundance of application-driven research, azobenzene photochemistry and the isomerization mechanism remain topics of investigation. Additional substituents on the azobenzene ring system change the spectroscopic properties and isomerization mechanism. This critical review details the studies completed to date on the 3 main classes of azobenzene derivatives. Understanding the differences in photochemistry, which originate from substitution, is imperative in exploiting azobenzene in the desired applications.
2,062 citations
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1,113 citations
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TL;DR: A series of 10 2,3,4,5-tetraphenylsiloles with different 1,1-substituents [XYSi(CPh)4] were prepared, and three of them were characterized crystallographically as mentioned in this paper.
Abstract: A series of ten 2,3,4,5-tetraphenylsiloles with different 1,1-substituents [XYSi(CPh)4] were prepared, and three of these, i.e., 1,1,2,3,4,5-hexaphenylsilole [X = Y = Ph (3)], 1-ethynyl-1,2,3,4,5-pentaphenylsilole [X = Ph, Y = C⋮CH (15)], and 1,1-bis(phenylethynyl)-2,3,4,5-tetraphenylsilole [X = Y = C⋮CPh (18)], were characterized crystallographically. The ground- and excited-states of the siloles were influenced by the inductive effect of the 1,1-substituents: with an increase in their electronegativity, the absorption and emission spectra of the siloles bathochromically shifted. A simple and reliable TLC-based method was developed for measurement of the solid-state luminescence spectra of the siloles. When molecularly dissolved in common solvents at room temperature, all the siloles were practically nonemissive (“off”). When poor solvents were added, the silole molecules clustered into nanoaggregates, which turned the emission “on” and boosted the photoluminescence quantum yields by up to 2 orders of m...
1,048 citations