Kazushi Kinbara

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTToward Intelligent Molecular Machines: Directed Motions of Biological and Artificial Molecules and AssembliesKazushi Kinbara and Takuzo AidaView Author Information Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan, and PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan Cite this: Chem. Rev. 2005, 105, 4, 1377–1400Publi

X-ray crystallographic studies were carried out for seven conglomerates, seventeen racemic compounds, and four enantiomerically pure salts of chiral primary amines with achiral monocarboxylic acids. The crystal structures of the conglomerate salts revealed that these crystals can be regarded as being an assembly of a characteristic columnar hydrogen-bond network in which the ammonium cations and the carboxylate anions are aligned around a 2-fold screw axis (21-column). On the other hand, the cry

ADVERTISEMENT RETURN TO ISSUEEditorialNEXTIntroduction: Molecular MotorsRyota Iino*Ryota IinoInstitute for Molecular Science and The Graduate University for Advanced Studies (SOKENDAI)*E-mail: [email protected]More by Ryota IinoView Biographyhttp://orcid.org/0000-0003-0110-5704, Kazushi Kinbara*Kazushi KinbaraTokyo Institute of Technology*E-mail: [email protected]More by Kazushi KinbaraView Biography, and Zev Bryant*Zev BryantStanford University*E-mail: [email protected]More by Zev BryantView Bi

EZ-Photoisomerization has been attained for several kinds of salts of α,β-unsaturated carboxylic acids with amines. This photoreaction has been proven to be an effective method for preparing (Z)-isomers from ammonium (E)-α,β-unsaturated carboxylates. The isomerizability is strikingly altered upon changing the ammonium group, which implies that the crystal structure affected the reactivity to a considerable extent. However, the cavity in the crystal has been found to have less influence than expe

Ferrocene, a double-decker organometallic compound that generates angular motion, can be used as a unique rotary module for molecular machines. By interlocking a ferrocene-based rotary module with a photochromic unit, we have developed novel molecular machines that operate via power-conversion mechanisms. This design strategy, which mimics real machines in our daily life, allows for remote control of molecular events.

Upon confinement of a trinuclear gold(I) pyrazolate complex in a hexagonal silicate channel, the luminescence center formed by a AuI–AuI metallophilic interaction is not only protected against thermal disruption but also strongly encouraged to self-recover from a heat-induced structural damage. This nanoscopic template effect is negligible for a lamellar silica framework.

The crystal structures of the diastereomeric salts of 1-arylethylamines with mandelic acid or p-methoxymandelic acid have been studied. This revealed that there was correlation between the efficiencies of the optical resolutions of the amines with the resolving reagents and the crystal structures of the salts. A characteristic hydrogen-bond layer, consisting of stable columnar structures and having a planar boundary surface, was found to be common to the less-soluble salt crystals; these crystal

A novel resolving agent, 2-naphthylglycolic acid (2-NGA), was designed for p-substituted 1-arylethylamines on the basis of the consideration that a rigid and large naphthyl group would be favorable for the close packing of supramolecular hydrogen-bond sheets formed between the carboxy groups of 2-NGA and the amino groups of p-substituted 1-arylethylamines. Racemic 2-NGA was readily available from commercially available raw materials, and both enantiopure forms could be obtained by simple diaster

Oligo(ethylene glycol) monotosylates are prepared on a multigram scale and in high purity with a new chromatography-free process.

Enantiopure cis-1-aminoindan-2-ol was selected as a basic resolving agent for racemic 2-arylalkanoic acids on the basis that its rigid cis-conformation would favor the formation of a supramolecular hydrogen-bonded column, in which chiral discrimination of the racemic carboxylate would occur. It was found that this amino alcohol possesses high resolving efficiency for a variety of racemic acids; also, X-ray crystallographic analyses of the diastereomeric salts showed that a columnar hydrogen-bond

As a result of systematic studies on the optical resolution of racemates via crystallization, we have found that in many cases, common characteristic hydrogen-bond networks were formed in the less-soluble diastereomeric salts or conglomerates. Design of resolving/derivatizing agents could be achieved on the basis of the concept of crystal engineering, by which molecules were designed to achieve stable hydrogen-bond networks with target racemates.

The resolution of 2-arylalkanoic acids by (1R,2S)-2-amino-1,2-diphenylethanol has been studied. It has been found that the position of a substituent on the aromatic group of the acids affects resolution efficiency to a considerable extent. Crystal structure analysis of the diastereomeric salts has revealed that a columnar hydrogen-bond network is commonly formed in the diastereomeric salts studied. A detailed analysis of the hydrogen-bond networks formed in the diastereomeric salts has enabled c