Biomedical subjects

Shinya Oshita

Publications and source records attributed to Shinya Oshita.

3 recordsLinked to original sources

PubMed2006

Orientational control of guest molecules in an organic intercalation system by host polymer tacticity.

Four kinds of stereoregular poly(muconic acid)s, which are synthesized by topochemical polymerization and subsequent solid-state hydrolysis, are used as the organic host materials for intercalation. We describe the reaction behavior and layered structure of intercalation compounds using stereoregular poly(muconic acid)s and n-alkylamines as host and guest, respectively. The packing structure of the guest alkylamines was determined by X-ray diffractions as well as IR and Raman spectroscopies. We have found that the orientation of the guest molecules is controlled by the host polymer tacticity, depending on the structure of the two-dimensional hydrogen-bonding network formed in the polymer sheets of the crystals.

Journal Article↗

PubMed2006

Fluorescence from aromatic compounds isolated in the solid state by double intercalation using layered polymer crystals as the host solid.

Poly(muconic acid)s, stereoregular polymer crystals obtained by topochemical polymerization using supramolecular control, function as the layered host solids for organic intercalation, in which alkylamines as the guest species are reversibly inserted into them through an acid-base interaction. We now report a double-intercalation method using alkylamine and pyrene as the guests to control the fluorescence property in the solid state. An aromatic compound can be separately introduced into the hydrophobic layers of the ammonium polymer crystals. The aromatic molecules, which are sandwiched between two alkyl layers, show fluorescence emission from the single molecule but not the excimer. This method can be applied to various organic photofunctional materials showing unique fluorescence properties.

Journal Article↗

PubMed2002

A novel organic intercalation system with layered polymer crystals as the host compounds derived from 1,3-diene carboxylic acids.

A new type of organic intercalation system using poly(muconic acid) and poly(sorbic acid) crystals as the host compounds is described. The layered polymer crystals as the host are derived from benzyl-, dodecyl-, or naphthylmethylammonium salts of (Z,Z)-muconic or (E,E)-sorbic acids by topochemical polymerization. The subsequent solid-state hydrolysis of the resulting ammonium polymer crystals provides the corresponding carboxylic acid polymer crystals. When alkylamines are reacted with poly(muconic acid) or poly(sorbic acid) crystals dispersed in methanol at room temperature for a few hours, the intercalation proceeds to give layered ammonium polymer crystals via solid-state reactions, in which the polymers maintain a layered structure throughout. The interplanar spacing value of the polymer crystals changes according to the size of the guest molecules; that is, it exactly depends on the carbon number of the alkylamines used for each reaction of poly(muconic acid) or poly(sorbic acid) crystals. The stacking structure of alkyl chains with a tilt in the intercalated alkylammonium layers exists irrespective of the chemical and crystal structures of the host polymers. The intercalation of higher alkylamines into poly(muconic acid) crystals proceeds fast and quantitatively, while the conversion is dependent on the reaction conditions such as the structure and amount of the amine and the reaction time during the intercalation with poly(sorbic acid) crystals, due to the difference in the repeating layered structures of these polymer crystals. Some functional amines are also used as the guest molecules for this organic intercalation system.

Journal Article↗