Hideko Koshima

Mechanically responsive crystals have been increasingly explored, mainly based on photoisomerization. However, photoisomerization has some disadvantages for crystal actuation, such as a slow actuation speed, no actuation of thick crystals, and a narrow wavelength range. Here we report photothermally driven fast-bending actuation and simulation of a salicylideneaniline derivative crystal with an <i>o</i>-amino substituent in enol form. Under ultraviolet (UV) light irradiation, these thin (<20 μm)

Mechanically responsive materials have been investigated extensively over the past two decades. Diversification of actuation modes is essential for the practical application of mechanical materials. Polymorphic crystals with different crystal structures composed of the same compound can exhibit distinct mechanical motions. Here, we focused on two polymorphs of a salicylideneaniline derivative with a 4-fluoro substituent in enol form, 1α and 1β, and investigated their different photomechanical be

The photomechanical bending of crystals of a stilbene-type compound substituted with anthracene and indanone groups, (E)-2-(9-anthrylmethylene)-1-indanone (trans-1), was investigated. When a narrow plate-like microcrystal was irradiated with ultraviolet (UV) light at 365 nm, the crystal gradually bent away from the light source and finally reached a semicircular shape after more than 10 min. A larger rod-like crystal, approximately 10 mm in length, also exhibited a slight bending motion. The ces

Chloroform solutions of dicyclohexyl-18-crown-6 (DC18C6), dibenzo-18-crown-6 (DB18C6) and 18-crown-6 (18C6) efficiently extracted iron(III), gold(III), gallium(III), thallium(III) and antimony(V) from solution in hydrochloric acid. Extraction with 15-crown-5 (15C5) and 12-crown-4 (12C4) was poor. Antimony(III) in the presence of titanium(III) chloride was efficiently extracted only with DC18C6. When tervalent iron, gold, gallium and thallium were extracted from acidic lithium chloride solution,

A series of benzimidazoles containing aryl and heteroaryl substituents were efficiently and quickly synthesized by condensation of 1,2phenylenediamine with carboxylic acids in the presence of polyphosphoric acid under microwave irradiation.2][3] The signature of microwave-enhanced chemistry is that the rates of reactions involving polar components are usually very fast.Reactions that require hours or days of conventional heating may often be accomplished in minutes by microwave heating.Benzimida

Abs tract -Microwave irradiation for several minutes caused reaction of diarylamines with carboxylic acids in the presence of zinc chloride to give 9substituted acridines in good yield.Microwave-assisted organic synthesis has gained in popularity in recent years because microwave irradiation was found to accelerate remarkably a wide variety of reactions. 1,2Heterocyclic compounds such as quinolines and quinoxalines were also rapidly prepared by microwave heating. 3-9Acridines are materials for s

Molecular crystals are attractive as mechanically responsive materials, contrary to their appearance as hard and fragile objects. We have intensively developed various photomechanical crystals such as azobenzene and salicylideneaniline based on photoisomerization over the recent decade. Not only bending but also various motions such as robot-like locomotion are possible by thermal phase transition as well as photo-triggered phase transition. Crystals have the advantage of exerting greater mechan