Tsukasa Hatano

Publications (13)62.68 Total impact

• Article: A columnar liquid crystal based on triphenylphosphine oxide--its structural changes upon interaction with alkaline metal cations.

  Tsukasa Hatano, Takashi Kato
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  ABSTRACT: A triphenylphosphine oxide (TPPO) compound bearing 3,4,5-tridodecyloxybenzyloxy moieties exhibits a columnar liquid crystalline phase, and by changing its self-assembled structure, is responsive to alkaline metal cations due to cation-phosphine oxide interactions.
  Chemical Communications 04/2006; · 6.17 Impact Factor
• Article: Superstructural Poly(pyrrole) Assemblies Created by a DNA Templating Method

  Ah-Hyun Bae, Tsukasa Hatano, Munenori Numata, Masayuki Takeuchi, Seiji Shinkai
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  ABSTRACT: It was found that DNAs can act as attractive templates for oxidative polymerization of pyrrole and result in novel higher-order superstructures composed of the DNA padding and the conjugate polymer outer layer. Furthermore, the resultant DNA/poly(pyrrole) composite can be deposited on an ITO electrode. The TEM and SEM observations have shown that oxidative polymerization creates a variety of superstructural poly(pyrrole) assemblies such as nanosized rodlike, circular, or supercoiled structures, reflecting the higher-order conformations of DNAs acting as the templates. The findings establish that the morphology of the conjugate polymer assemblies are controllable by a change in the DNA morphology used as their templates. The deposition of DNAs onto the ITO electrode was characterized by (1) ATR IR absorption bands assignable to DNA, (2) XPS binding energy of the phosphate group assignable to DNAs, and (3) binding of ethidium bromide (EB) to DNAs as detected by UV−vis spectroscopy and confocal laser scanning microscope (CLSM). The further detailed examination of the SEM pictures has established that the composite consists of a fibrous structure or its bundled structure, depending on the polymerization conditions. Interestingly, the ITO electrode modified by the DNA/poly(pyrrole) composite showed the CV responsiveness to DNA intercalators, indicating a potential to apply this system to a new amperometric DNA-based sensor.
  01/2005;
• Article: Polyaniline superstructures created by a templating effect of organogels.

  Chun Li, Tsukasa Hatano, Masayuki Takeuchi, Seiji Shinkai
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  ABSTRACT: The use of organogelators to template chiral and achiral polyaniline superstructures via the electrostatic interaction between anionic sulfonated polyaniline and a cationic gelator is described.
  Chemical Communications 11/2004; · 6.17 Impact Factor
• Article: Helical structures of conjugate polymers created by oxidative polymerization using synthetic lipid assemblies as templates.

  Tsukasa Hatano, Ah-Hyun Bae, Masayuki Takeuchi, Norifumi Fujita, Kenji Kaneko, Hirotaka Ihara, Makoto Takafuji, Seiji Shinkai
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  ABSTRACT: The morphology of conjugate polymers (such as poly(ethylenedioxythiophene), poly(pyrrole), and poly(aniline)) can be controlled in their polymerization processes, by applying the concept of the templating method to oxidative polymerization. As oxidative polymerization of these monomers produces cationic intermediates, the anionic assemblies can act as potential templates due to the mutual electrostatic attractive force. Oxidative polymerization of ethylenedioxythiophene (EDOT), pyrrole, and aniline was carried out using helical superstructures of synthetic lipid assemblies as templates. Interestingly, we have found that oxidative polymerization of these monomers results in novel polymeric aggregates, such as a helical-tape structure and an intertwined helical structure, and that both the right-handed and left-handed helical structures can be created by a change in the hydrophilic head groups. This is the first example of helical superstructures composed of conjugate polymers that have been designed utilizing a convenient templating method.
  Chemistry 11/2004; 10(20):5067-75. · 5.93 Impact Factor
• Article: Electrochemical fabrication of single-walled carbon nanotubes-DNA complexes by poly(ethylenedioxythiophene) and photocurrent generation by excitation of an intercalated chromophore.

  Ah-Hyun Bae, Tsukasa Hatano, Naotoshi Nakashima, Hiroto Murakami, Seiji Shinkai
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  ABSTRACT: It was found that single-walled carbon nanotubes (SWNTs) solubilized into water by complexation with DNA (salmon testes) can be readily deposited on the ITO electrode by electrochemical oxidative polymerization of ethylenedioxythiophene (EDOT). The driving force for this novel deposition is an electrostatic interaction between the anionic charges of wrapping DNA and the cationic charges of poly(EDOT) formed in the oxidative polymerization process. The presence of poly(EDOT), SWNTs and DNA in the composite was confirmed by measurements of UV-Vis, IR, resonance Raman spectra, cyclic voltammetry (CV) and confocal laser scanning microscopy (CLSM). The composite adsorbed a DNA intercalator (ethidium bromide: EB) very efficiently, which is regarded to be further evidence for inclusion of DNA. The surface morphology, characterized by CLSM, SEM and AFM, featured the network structure consisting of 0.5-ca. 10 microm nanorods. Very interestingly, we found that photoexcitation of EB bound to the DNA generates the photocurrent, indicating that the excited energy of EB is injected into SWNTs, which is collected by the electroconductive poly(EDOT) film on the ITO electrode. We believe, therefore, that the present system is a very convenient method to explore new materials related to redox and photochemical functions.
  Organic & Biomolecular Chemistry 05/2004; 2(8):1139-44. · 3.70 Impact Factor
• Article: Helical superstructure of conductive polymers as created by electrochemical polymerization by using synthetic lipid assemblies as a template.

  Tsukasa Hatano, Ah-Hyun Bae, Masayuki Takeuchi, Norifumi Fujita, Kenji Kaneko, Hirotaka Ihara, Makoto Takafuji, Seiji Shinkai
  Angewandte Chemie International Edition 02/2004; 43(4):465-9. · 13.45 Impact Factor
• Article: Improvement of Quantum Yields for Photoinduced Energy/Electron Transfer by Isolation of Self-Aggregative Zinc Tetraphenyl Porphyrin-Pendant Polymer Using Cyclodextrin Inclusion in Aqueous Solution

  Toshifumi Konishi, Atsushi Ikeda, Masayoshi Asai, Tsukasa Hatano, Seiji Shinkai, Mamoru Fujitsuka, Osamu Ito, Youichi Tsuchiya, Jun-ichi Kikuchi
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  ABSTRACT: Cyclodextrin inclusion for self-aggregative sensitizers was found to improve quantum yields for photoinduced energy/electron transfer by the isolation of sensitizers in an aqueous solution. In water, cyclodextrin derivatives can prevent self-aggregation of sensitizers, which decreases the total quantum yields for photoinduced energy/electron transfer by fast self-quenching of singlet excited states, and anionic water-soluble zinc tetraphenyl porphyrin-pendant polymers (poly-ZnP) show self-aggregation and self-quenching of the singlet excited state of the zinc tetraphenyl porphyrin moiety. With the addition of 2,3,6-tri-O-methyl-β-cyclodextrin (TMBCD) to an aqueous solution of poly-ZnP, cyclodextrin inclusion induces isolation of the zinc tetraphenyl porphyrin moiety, which extends extensively the lifetime of the singlet excited state. In the presence of TMBCD, the quantum yield for photoinduced triplet−triplet (T−T) energy transfer (Φen) from photoexcited poly-ZnP to O2 was enhanced remarkably from 0.11 (without TMBCD) to 0.57 (with TMBCD) in air-saturated water. Also, the quantum yield for electron transfer (Φet) from photoexcited poly-ZnP to water-soluble γ-cyclodextrin-bicapped [60]fullerene (C60/γ-CD) increased from 0.095 (without TMBCD) to 0.20 (with TMBCD) in Ar-saturated water. Through quantitative photolysis, it has been revealed that the quantum yield for the formation of triplet excited poly-ZnP (ΦT) is increased greatly to produce large Φen and Φet values with the addition of TMBCD to the solution. Demonstrated is a new strategy to improve quantum yields for photoinduced reactions using cyclodextrin derivatives as an isolator/stabilizer of photoexcited self-aggregative dyes.
  09/2003;
• Article: Facile deposition of [60]fullerene and carbon nanotubes on ITO electrode by electrochemical oxidative polymerization of ethylenedioxythiophene.

  Tsukasa Hatano, Ah-Hyun Bae, Kazunori Sugiyasu, Norifumi Fujita, Masayuki Takeuchi, Asushi Ikeda, Seiji Shinkai
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  ABSTRACT: It was found that [60]fullerene encapsulated in p-sulfonatocalix[8]arene and single-walled carbon nanotubes (SWNTs) solubilized by sodium dodecylsulfate can be readily deposited on the ITO electrode by electrochemical oxidative polymerization of ethylenedioxythiophene (EDOT) without chemical modification of these carbon clusters. The driving force for the deposition is an electrostatic interaction between the anionic complexes and the cationic charges of poly(EDOT) formed in the oxidative polymerization process. The surface morphology was thoroughly characterized by scanning electron micrograph: the [60]fullerene/poly(EDOT) film is covered by nano-particles with 20-100 nm diameters whereas the SWNTs/poly(EDOT) film is covered by nanorods with several microm length and ca. 100 nm diameter. The results indicate that the anionic complexes act as nuclei for the polymer growth in the oxidation polymerization. Interestingly, when these modified ITO electrodes were photoirradiated, the appearance of a photocurrent wave was observed. The action spectra showed that the photoexcited energy of [60]fullerene or SWNTs is efficiently collected by the electroconductive poly(EDOT) film and transferred to the ITO electrode.
  Organic & Biomolecular Chemistry 08/2003; 1(13):2343-7. · 3.70 Impact Factor
• Article: Nano-rod structure of poly(ethylenedioxythiophene) and poly(pyrrole) as created by electrochemical polymerization using anionic porphyrin aggregates as template.

  Tsukasa Hatano, Masayuki Takeuchi, Atsushi Ikeda, Seiji Shinkai
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  ABSTRACT: It was found that a one-dimensional rodlike structure of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) in water acts as a powerful template for electrochemical polymerization of ethylenedioxathiophene (EDOT) and pyrrole on an ITO electrode. Examination using CV and UV-vis spectroscopic examinations established that J-aggregated TPPS molecules are entrapped in the resultant poly(EDOT) and poly(pyrrole) films. SEM observation established that these monomers are electrochemically oxidized to grow up to a nanosized rodlike structure, reflecting the aggregation structure of TPPS. [structure: see text]
  Organic Letters 06/2003; 5(9):1395-8. · 5.86 Impact Factor
• Article: Facile deposition of [60]fullerene on the electrode by electrochemical oxidative polymerization of thiophene.

  Tsukasa Hatano, Masayuki Takeuchi, Atsushi Ikeda, Seiji Shinkai
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  ABSTRACT: It was found that [60]fullerene encapsulated in anionic calix[8]arenes can be readily deposited by electrochemical oxidative polymerization of ethylenedioxythiophene: the resultant electrode generates a photocurrent wave (ca. 100 nA cm(-2)) in response to visible light irradiation.
  Chemical Communications 03/2003; · 6.17 Impact Factor
• Article: Photo-induced colour generation and colour erasing switched by the sol-gel phase transition.

  Tao Yi, Kazuki Sada, Kazunori Sugiyasu, Tsukasa Hatano, Seiji Shinkai
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  ABSTRACT: The controlled colour generation and colour erasing phenomena of alkylammonium polyoxomolybdate complexes were first observed in the trans-(1R,2R)-1,2-bis(undecylcarbonylamino)cyclohexane organogel system using the sol-gel phase transition.
  Chemical Communications 03/2003; · 6.17 Impact Factor
• Article: Supramolecular design of a porphyrin–[60]fullerene photocurrent generation system on a DNA scaffold fabricated by a conjugate polymer film

  Ah-Hyun Bae, Tsukasa Hatano, Kazunori Sugiyasu, Takanori Kishida, Masayuki Takeuchi, Seiji Shinkai
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  ABSTRACT: DNA which binds monocationic [60]fullerene (1) and tetracationic porphyrin (TMPyP) was readily fabricated by electrochemical oxidative polymerization of 3.4-ethylenedioxythiophene (EDOT) and the resultant poly(EDOT) composite was deposited on an ITO electrode as a stable thin film. Spectral and CV analyses established that one 1 and one TMPyP are bound per 57 nucleobase units, that is, every three pitches of DNA. Photoirradiation of this 1/TMPyP/DNA-poly(EDOT) film generated a photocurrent in 3.8% quantum yield, which was much higher than those obtained from 1/DNA and TMPyP/DNA systems. One can conclude, therefore that the photoexcited energy of TMPyP is transferred to 1, which is collected by the electron-conducting poly(EDOT) film. The present paper shows that DNA is useful as a scaffold to arrange redox-active couples in a one-dimensional matrix.Graphical abstract
  Tetrahedron Letters 46(18):3169-3173. · 2.68 Impact Factor
• Article: A porphyrin-based gelator assembly which is reinforced by peripheral urea groups and chirally twisted by chiral urea additives

  Shun-ichi Tamaru, Shin-ya Uchino, Masayuki Takeuchi, Masato Ikeda, Tsukasa Hatano, Seiji Shinkai
  Tetrahedron Letters 43(20):3751-3755. · 2.68 Impact Factor