Naohiro Terasawa

Calamitic and discotic mesophases formed by kinetically controlled rod?disc alternation of molecular shape in a triphenylene?azobenzene mesogenic systemElectronic supplementary information (ESI) available: DSC traces and photos of mesophases. See http://www.rsc.org/suppdata/cc/b3/b301862h/

A triphenylene mesogen with the peripheral azobenzene units was found to show kinetically controlled bimesomorphism, with a metastable smectic and a stable hexagonal columnar (Colh) phases on cooling, which is caused by the rod–disc alternation of the molecular shape.

Synthesis of novel polymethacrylates bearing cyclic perfluoroalkyl groups

Novel fluorinated methacrylic polymers and copolymers were prepared. Perfluoro(2-pyrrolidinopropionyl fluoride) and perfluoro(3-pyrrolidinopropionyl fluoride) were reduced to the corresponding 1,1-dihydroperfluoro-alcohols, which were then reacted with methacryloyl chloride to give the methacrylates. The homopolymers and the copolymers with methyl methacrylate were obtained by a radical polymerization. The tough polymer films prepared by solution casting showed excellent water repellency with contact angles above 100°.

Mesomorphic properties of symmetrical and asymmetrical triphenylene homologues possessing fluoroalkylated side chains

Two types of homologues (symmetrical and asymmetrical in rotational symmetry) of novel triphenylene compounds possessing fluoroalkyl and alkyl side chains were synthesized via an alternative method. X‐ray diffraction and DSC measurements showed that these homologues are thermotropic liquid crystals with a hexagonal columnar (Colh) mesophase. The phase transition temperatures (Colh–Iso) for both symmetrical and asymmetrical fluoroalkyloxytriphenylenes increase to about 180°C, and are independent of fluoromethylene chain and the rotational symmetry of chemical structure. The Colh phase of symmetrical and asymmetrical fluoroalkyloxytriphenylenes possessing three fluoroalkyl side chains are more stable than fluoroalkyloxytriphenylenes possessing six fluoroalkyl side chains and alkyloxytriphenylenes. The X‐ray diffraction patterns for symmetrical and asymmetrical fluoroalkyloxytriphenylenes, fluoroalkyloxytriphenylenes and alkyloxytriphenylenes in the wide‐angle region are compared.

Trifluoromethylation by bis(trifluoroacetyl) peroxide of polymers bearing benzene rings

Bis(trifluoroacetyl) peroxide was prepared in good yield by the reaction between trifluoroacetic anhydride and sodium peroxide under anhydrous conditions. Polymers bearing benzene rings, polystyrene, poly(phenylene oxide) and poly(diphenylacetylene) were modified chemically by the peroxide. The resulting trifluoromethylated polymers have good solubilities in common organic solvents, and their cast films have good water repellency. The trifluoromethylated poly(diphenylacetylene)s have high gas and vapor permeabilities.

Synthesis and applications of bis(perfluorodecalin-1-carbonyl) peroxide

Abstract New bis(perfluorodecalin-1-carbonyl) peroxide (PFDC-PO) was prepared by the reaction of hydrogen peroxide with perfluorodecalin-1-carbonyl chloride, obtained from the chlorination of the corresponding carboxylic acid and phosphorus oxychloride in the presence of DMF. A kinetic study showed that PFDC-PO decomposes homolytically with a three-bond fission. Heptadecafluorodecahydro-1-naphthyl (F-DECALYL) end-capped oligomers were prepared by the reaction of PFDC-PO with monomers such as acrylic acid (ACA), N , N -dimethylacrylamide (DMAA), 3-methacryloxy-2-hydroxypropyltrimethylammonium chloride, and N -(1,1-dimethyl-3-oxobutyl)acrylamide (DOBAA) via a radical process. Interestingly, these F-DECALYL end-capped oligomers obtained were soluble in water and common organic solvents, although parent perfluorodecalin is insoluble in water and common organic solvents except hexane. F-DECALYL end-capped ACA oligomer was easily soluble in water and reduced the surface tension of water effectively. Additionally, F-DECALYL end-capped ACA oligomer was found to enhance dramatically luminol chemiluminescence light yield compared to the corresponding linear fluoroalkylated ACA oligomer. F-DECALYL end-capped DMAA and DOBAA oligomers were insoluble in water; however, these oligomers were soluble in common organic solvents. Especially, F-DECALYL end-capped DOBAA oligomer was found to form a monomolecular film at the air–water interface.

Preparation and characteristics of perfluorodiacetylene Langmuir-Blodgett films

Abstract The surface pressure–area curve for the novel perfluorodiacetylene, C24F42, showed that a monolayer was formed on the surface of the water. The monolayer was deposited on KRS-5, Al and quartz plates by the Langmuir–Blodgett (LB) technique. The LB film on the KRS-5 plate showed excellent water repellency with a contact angle of 162°. Comparison of the reflection–absorption and transmission i.r. spectra showed that the difluoromethylene chains in the C24F42 LB film were oriented perpendicular to the substrate surface. The C24F42 LB film on the quartz plate was polymerized by u.v. irradiation giving a highly electroconductive film without doping or further treatment.

Preparation and surface characteristics of perfluoroalkane Langmuir-Blodgett films

Abstract Surface pressure-area curves for the perfluoroalkanes C16F34, C20F42 and C24F50 showed that monolayers were formed on the sur water. The monolayers of C20F42 and C24F30 were deposited on various substrates by the Langmuir-Blodgett (LB) technique; LB films on hydrophobized mica show excellent water repellency with contact angles of water of 155 ° and 153 ° respectively. It was shown by comparison of the reflection-absorption and transmission IR spectra that difluoromethylene chains in the perfluoroalkane LB films are oriented perpen- dicular to the substrate.

Oligomerization reactions of perfluorovinylamines catalyzed by fluoride ions

Abstract The fluoride ion catalyzed Oligomerization of F -vinylamines, such as F-(N,N -dimethylvinylamine), F-(N -vinylmorpholine) and F-(N -vinylpyrrolidine), was investigated. It was found that dimers were obtained in high yields when the reaction was conducted in aprotic polar solvents, especially in DMF using cesium fluoride as a fluoride ion source. Attempts to obtain oligomers higher than dimers failed. The absence of higher oligomers is discussed in stereoelectronic and steric terms by comparison with the analogous Oligomerization of hexafluoropropene. Unexpected results obtained in the reaction of F-(N,N -dimethylvinylamine) with the hexafluoropropene dimer F -2-methyl-2-propene are also included.

Synthesis of novel liquid crystals having the perfluoropyrrolidino group

Abstract Novel liquid crystals which have the perfluoropyrrolidino group, a heterocyclic perfluoroalkyl group, and which show smectic phases have been synthesized with perfluoro-(2-pyrrolidinopropionyl fluoride) as one of the starting materials. Analogues with a polymerizable functional group also have been prepared and polymerized to give side chain liquid crystal polymers.

Synthesis of a persistent perfluoroalkyl radical by electrochemical fluorination

A persistent perfluoroalkyl radical, perfluoro-3-ethyl-2,4-dimethyl-3-pentyl, was synthesized by the electrochemical fluorination of a mixture of hexafluoropropene trimers in the presence of a large amount of sodium fluoride.