Tomoyuki Ikai

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTStructure Control of Polysaccharide Derivatives for Efficient Separation of Enantiomers by ChromatographyTomoyuki Ikai† and Yoshio Okamoto*†‡View Author Information EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan, and College of Material Science and Chemical Engineering, Harbin Engineering University, 145 Nantong St. Harbin 150001, P. R. China.* To whom correspondence should be addressed. Mailing address: EcoT

We report the synthesis of one-dimensional supramolecular polymers composed of one-handed helical macromolecules bearing fluorescent pendant groups and the generation of circularly polarized light on the basis of hierarchical chiral amplification starting from a tiny amount of chiral substituent. Copolymerization of benzo[1,2-<i>b</i>:4,5-<i>b</i>']dithiophene-appended achiral/chiral isocyanides (99:1, mol/mol) with a solid-state photoluminescence feature afforded submicrometer supramolecular fi

Here we report an efficient synthesis of optically active ladder-type molecules and polymers through intramolecular cyclization of chiral triptycenes containing bis[2-(4-alkoxyphenyl)ethynyl]phenylene units. The electrophile-induced cyclization reactions are directed away from the bridgehead carbon atoms of triptycene by steric factors, thereby producing one-handed twisted ladder units without any detectable byproducts. Moreover, the quantitative and regioselective nature of this intramolecular

Any polymers composed of racemic repeating units are obviously optically inactive and hence chiral functions, such as asymmetric catalysis, will not be expected at all. Contrary to such a preconceived notion, we report an unprecedented helical polymer-based highly enantioselective organocatalyst prepared by polymerization of a racemic monomer with no catalytic activity. Both the right- and left-handed helical poly(biarylylacetylene)s (PBAs) composed of dynamically racemic 2-arylpyridyl-<i>N</i>-

We report the unprecedented synthesis of one-handed helical spiro-conjugated ladder polymers with well-defined primary and secondary structures, in which the spiro-linked dibenzo[a,h]anthracene fluorophores are arranged in a one-handed twisting direction, through quantitative and chemoselective acid-promoted intramolecular cyclizations of random-coil precursor polymers composed of chiral 1,1'-spirobiindane and achiral bis[2-(4-alkoxyphenyl)ethynyl]phenylene units. Intense circular dichroism (CD)

A series of chiral fluorescent polymers containing optically active triptycene units in the main chain were synthesized via Sonogashira-Hagihara coupling copolymerizations of (<i>R</i>,<i>R</i>)- or (<i>S</i>,<i>S</i>)-2,6-diethynyltriptycene with a range of diiodoaryls. Their optical and chiroptical properties were investigated under various solution conditions. We observe that these polymers emitted circularly polarized light owing to the chiral triptycene framework with a handed twisted rigid

A series of d-glucose-bound optically active π-conjugated polymers (poly-Tr) were synthesized by ternary copolymerization of 2,5-diiodothiophene with diethynyl monomers containing a chiral and an achiral biphenyl unit using the Sonogashira coupling reaction. The effect of the chiral and achiral biphenyl contents on the chiral amplification in the preferred-handed helix formation ("the sergeants and soldiers effect") was investigated by comparing the circular dichroism (CD) and circularly polariz

A racemic monomer-based optically inactive polyacetylene folds into a one-handed helix assisted by a nonracemic alcohol, which can separate various enantiomers as a chiral stationary phase in chromatography. The chiral-resolving power is virtually identical to that of the enantiopure monomer-based one-handed helical polyacetylene. Because of its unique static memory of the induced helicity, the original racemic polyacetylene expresses an auto-evolution of its helical handedness over time, and at

The hybrid bead-type chiral packing material (CPM) for preparative enantioseparation has been prepared from the cellulose 3,5-dimethylphenylcarbamate containing a small number of 3-(triethoxysilyl)propyl groups in the presence of tetraethyl orthosilicate, by a sol-gel reaction in an aqueous surfactant solution. The obtained hybrid bead-type CPM was packed into a column and evaluated by high-performance liquid chromatography. When compared with the commercially available Chiralpak IB, which is pr

A series of dynamic helical homo- and copolymers of chiral and/or achiral biphenylylacetylenes (PBPAs) bearing achiral methoxymethoxy or acetyloxy groups at the 2,2′-positions along with a chiral or achiral alkyl ether or alkoxy carbonyl group at the 4′-position of the biphenyl pendants were synthesized. The effects of the chiral/achiral substituents at different positions on their helical structures and amplification of the helicity through covalent and further noncovalent chiral interactions f

Abstract Cellulose 3,5-dimethylphenylcarbamate bearing a small amount of 3-(triethoxysilyl)propyl residues was synthesized and effectively immobilized onto silica gel support for high-performance liquid chromatography by the polycondensation of triethoxysilyl groups. The immobilized chiral packing material (CPM) showed high chiral recognition as well as the conventional CPM prepared by coating the derivative onto silica gel, and can be used with a variety of eluents.

A pair of optically pure triptycene derivatives ((R,R)- and (S,S)-3) containing fluorescent pyrene-based π-conjugated pendant groups attached through amide spacers were prepared via a resolution step using chiral high-performance liquid chromatography. Their absorption, circular dichroism, photoluminescence and circularly polarized luminescence (CPL) properties were investigated under various solution conditions. (R,R)- and (S,S)-3 exhibited clear solvent- and concentration-dependences of the op