A5049704881- Synthesis and Properties of Aromatic Compounds
- Liquid Crystal Research Advancements
- Supramolecular Self-Assembly in Materials
- Polydiacetylene-based materials and applications
- Synthesis and characterization of novel inorganic/organometallic compounds
- Surface Chemistry and Catalysis
- Molecular spectroscopy and chirality
- Photochromic and Fluorescence Chemistry
- Supramolecular Chemistry and Complexes
- Photochemistry and Electron Transfer Studies
- Luminescence and Fluorescent Materials
- Surfactants and Colloidal Systems
- Synthesis and properties of polymers
- DNA and Nucleic Acid Chemistry
- Organoboron and organosilicon chemistry
- Porphyrin and Phthalocyanine Chemistry
- Photonic Crystals and Applications
- Spectroscopy and Quantum Chemical Studies
- Molecular Junctions and Nanostructures
- Chemical Synthesis and Analysis
- Mesoporous Materials and Catalysis
- Advanced NMR Techniques and Applications
- Fullerene Chemistry and Applications
- Conducting polymers and applications
- Organic Electronics and Photovoltaics
Chitose Institute of Science and Technology
2012-2023
Japan Science and Technology Agency
2003-2011
Tokyo Institute of Technology
2002-2011
Nagoya University
2005-2010
Nara Institute of Science and Technology
2002-2009
Osaka University
2006-2009
Kyoto University
2009
Fujitsu (Japan)
2006
Kumamoto University
2003
Idemitsu Kosan (Japan)
1998
We report the direct evidence for macromolecular helicity inversion of a helical poly(phenylacetylene) bearing l- or d-alanine pendants with long alkyl chain in different solvents by atomic force microscopy observations diastereomeric structures. The poly(phenylacetylene)s induced polar and nonpolar self-assembled into ordered, two-dimensional helix bundles controlled molecular packing, pitch, handedness on graphite upon exposure each solvent. deposited from solvent further inverted to...
A commodity plastic, syndiotactic poly(methyl methacrylate) (st-PMMA), has been found to fold into a right- or left-handed helix through the assistance of (R)- (S)-1-phenylethanol (1) and encapsulates fullerenes within its helical cavity form robust, processable, optically active peapod-like complex whose helicity is retained after removal chiral alcohols. Supporting information for this article available on WWW under http://www.wiley-vch.de/contents/jc_2002/2008/z703655_s.pdf from author....
A long-standing question in polymer chemistry has been addressed by AFM, which revealed the helical conformation, handedness, and pitch (0.92 nm) of title stereocomplex formed from a 1:2 mixture named polymers (it- st-PMMA). The results provide convincing evidence for triple-stranded helix (see structure against background AFM image) as plausible model stereocomplex.
Rigid-rodlike right (P)- and left (M)-handed helical polyisocyanides (P-poly-l-1 M-poly-l-1) prepared by the living polymerization of an enantiomerically pure phenyl isocyanide bearing l-alanine pendant with a long n-decyl chain (l-1) μ-ethynediyl Pt−Pd catalyst were found to block copolymerize l-1 d-1 in highly enantiomer-selective manner while maintaining narrow molecular weight distributions. The M-poly-l-1 preferentially copolymerized over antipode factor 6.4−7.7, whereas was P-poly-l-1...
We report the unprecedented helix-sense controlled polymerization of enantiomerically pure phenyl isocyanides bearing an l- or d-alanine pendant with a long alkyl chain. The achiral nickel catalyst diastereoselectively proceeds, resulting in either right- left-handed helical polymer, whose can be by solvent and temperature. Both diastereomeric polymers further self-assemble into lyotropic cholesteric liquid crystals opposite twist-senses. Consequently, macromolecular helicity mesoscopic,...
A hard twist: helical poly(phenylacetylene) with L- or D-alanine pendants a long alkyl chain showed an unprecedented change in the main-chain stiffness accompanied by inversion of sense polymer, resulting from "on and off" fashion intramolecular hydrogen-bonding networks polar nonpolar solvents.
Rigid and rodlike, helical polyacetylene molecules self-assemble hierarchically on graphite upon exposure to solvent vapors. Flat monolayers form epitaxially the basal plane of graphite, which further into chiral 2D bundles helices with controlled helicity (see picture). Supporting information for this article is available WWW under http://www.wiley-vch.de/contents/jc_2002/2006/z503136_s.pdf or from author. Please note: The publisher not responsible content functionality any supporting...
Two complementary homopolymers of chiral amidines and achiral carboxylic acids with m-terphenyl-based backbones were synthesized by the copolymerization a p-diiodobenzene derivative diethynyl monomers bearing amidine group carboxyl using Sonogashira reaction, respectively. Upon mixing in THF, homopolymer strands assembled into preferred-handed double helix through interstrand amidinium-carboxylate salt bridges, as evidenced its absorption, circular dichroism, IR spectra. In contrast, when...
Extensive research on the use of cyclodextrin for insulating π-conjugated polymer chains has been carried out. However, resulting polyrotaxanes do not exhibit high and constant covering ratios are generally insoluble in organic solvents. Here we demonstrate a new method synthesizing permethylated cyclodextrin-based involving polymerization linked rotaxane monomers. The insulated molecular wires obtained by this highly soluble solvents have ratio, rigidity, photoluminescence efficiency. A...
An optically inactive poly(4-carboxyphenyl isocyanide) (poly-1-H) changed its structure into the prevailing, one-handed helical upon complexation with active amines in dimethylsulfoxide (DMSO) and water, complexes show a characteristic induced circular dichroism polymer backbone region. Moreover, macromolecular helicity water aqueous organic solutions containing more than 50 vol % could be "memorized" even after complete removal of chiral (h-poly-1b-H), while that DMSO DMSO−water mixtures...
We report, herein, the design, synthesis, and properties of new materials directed toward molecular electronics. A transition metal-containing insulated wire was synthesized through coordination polymerization a Ru(II) porphyrin with an bridging ligand well-defined structure. The displayed not only high linearity rigidity, but also intramolecular charge mobility. Owing to unique bond, interconversion between monomer polymer states realized under carbon monoxide atmosphere or UV irradiation....
Controlling the one-handed helicity in synthetic polymers is crucial for developing helical polymer-based advanced chiral materials. We now report that an extremely small amount of biphenylylacetylene (BPA) monomers (ca. 0.3–0.5 mol %) allows complete control throughout polymer chains mostly composed achiral BPAs. Chiral substituents introduced at 2-position biphenyl units BPA positioned vicinity backbones contribute to a significant amplification bias, as interpreted by theoretical modeling...
Rodlike polymers with precisely defined architectures are ideal building blocks for self-assembled structures leading to novel nanometer-scale devices. We found that the living polymerization of a single isocyanide enantiomer bearing an l-alanine pendant long n-decyl chain simultaneously produced diastereomeric right- and left-handed helices different molecular weights narrow weight distributions. Each single-handed, rodlike helical polymer controlled length handedness isolated by facile...
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTWell-Defined Lyotropic Liquid Crystalline Properties of Rigid-Rod Helical PolyacetylenesKento Okoshi, Koichi Sakajiri, Jiro Kumaki, and Eiji YashimaView Author Information Yashima Super-structured Helix Project, Exploratory Research for Advanced Technology (ERATO), Japan Science Agency (JST), 101 Creation Core Nagoya, 2266-22 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-0003, Cite this: Macromolecules...
Going straight: A luminescent composite of poly(p-phenylenevinylene) (PPV) and amylose was synthesized by direct polymerization the precursor monomer in aqueous media presence amylose. The PPV–amylose consists a rigid-rod PPV segment threaded into flexible tube self-assembles liquid-crystalline phases. Supporting information for this article is available on WWW under http://www.wiley-vch.de/contents/jc_2002/2006/z602134_s.pdf or from author. Please note: publisher not responsible content...
It all makes sense: A dynamically racemic helical polymer crystallizes on graphite upon exposure to an organic solvent vapor, resulting in two-dimensional helix-bundle formation. The enantiomeric right- and left-handed blocks separated by reversals can be directly visualized AFM with molecular resolution. Supporting information for this article is available the WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z701546_s.pdf or from author. Please note: publisher not responsible content...
Solid-state films of chiral polysilanes undergo an optical inversion (see Figure) above a helix–helix transition temperature, determined by the polymer molecular weight and thermal processing. These could be used for re-writable or write-once, read-many data storage, depending on temperature. Supporting information this article is available WWW under http://www.wiley-vch.de/contents/jc_2089/2004/c0470_s.pdf from author. Please note: The publisher not responsible content functionality any...
We report a unique hierarchical amplification of chiral information from nonracemic guest to macromolecular helicity, followed by mesoscopic, supramolecular cholesteric twist in water. This remarkable involves two-step chirality transfer processes, which enable the detection and sensing an extremely small imbalance molecules. The helicity with excess single-handed helix was first induced positively charged, chromophoric poly(phenylacetylene), hydrochloride...
We report a unique macromolecule consisting of rodlike helical polyisocyanide backbone with narrow molecular weight distribution and rigid mesogenic chiral pendants linked via flexible spacer that exhibits lyotropic nematic latticelike new smectic (lat-Sm) liquid crystal phases at different concentrations. The unprecedented lat-Sm phase is associated the ordering both stiff polymer rigid-rod side groups. A detailed investigation films using X-ray scattering atomic force microscopy revealed...
The serum glycoprotein fetuin-A is an important inhibitor of extraosseous calcification. importance has been confirmed in null mice, which develop widespread calcification including the kidney. However, mechanism how protects kidneys from nephrocalcinosis remains uncertain. Here, we demonstrate that intratubular plays a role prevention proximal tubules. Although normal rat kidney did not express mRNA for fetuin-A, found punctate immunohistochemical staining mainly S1 segment pattern...
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTWell-Defined Phase Sequence Including Cholesteric, Smectic A, and Columnar Phases Observed in a Thermotropic LC System of Simple Rigid-Rod Helical PolysilaneKento Okoshi, Hiroyuki Kamee, Goro Suzaki, Masatoshi Tokita, Michiya Fujiki, Junji WatanabeView Author Information Department Polymer Chemistry, Tokyo Institute Technology, Ookayama, Meguro-ku, 152-8552, Japan; Graduate School Materials Science, Nara...
ADVERTISEMENT RETURN TO ISSUECommunication to the...Communication the EditorNEXTHelical Polymer Command Surface: Thermodriven Chiroptical Transfer and Amplification in Binary Polysilane Film SystemAnubhav Saxena, Guangqing Guo, Michiya Fujiki, Yonggang Yang, Akihiro Ohira, Kento Okoshi, Masanobu NaitoView Author Information Graduate School of Materials Science, Nara Institute Science Technology, 8916-5 Takayama, Ikoma, 630-0101, Japan, CREST-JST (Japan Technology Agency), 4-1-8 Hon-cho,...
We found that stereoregular isotactic poly(methyl methacrylate) (it-PMMA) (mm = 97%) and syndiotactic (st-PMMA) (rr 90%) with a narrow molecular weight distribution form stereocomplex in ionic liquids such as 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF6). The formation brought about the gelation of BMIPF6 was fully thermoreversible accompanied by sol−gel transition at around melting point crystalline evidenced differential scanning calorimetry polarized optical microscopy...
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTAnomalous Stiff Backbones of Helical Poly(phenyl isocyanide) DerivativesKento Okoshi*†‡, Kanji Nagai†§, Takashi Kajitani†, Shin-ichiro Sakurai†, and Eiji Yashima*†§View Author Information Yashima Super-structured Helix Project, Exploratory Research for Advanced Technology, Japan Science Technology Agency, Japan, Department Molecular Design Engineering, Graduate School Nagoya University, Chikusa-ku, 464-8603, Japan* To whom correspondence should be...
A series of optically active phenyl isocyanides bearing various chiral functional groups, such as l-alanine, l-alaninol, l-phenylalanine, and l-lactic acid residues, with a long n-decyl chain the pendants were prepared, these polymerized an achiral nickel catalyst (NiCl2) in organic solvents at different temperatures. The chiroptical properties structures resulting helical polyisocyanides investigated by circular dichroism (CD) IR spectroscopy revealed that Cotton effect signs intensities...