Chemically and thermally stable thin films of polyphthalocyanine were prepared by a simple evaporation-polymerization method. The rectifying characteristics of metal/semiconductor/ metal (MSM) type sandwich devices with the film were studied. A Schottky type device metal (Cu, Al, Ti)/polyphthalocyanine/Cu shows reproducible rectifying characteristics when Ti is selected as a counter electrode. The reproducibility is improved by pre-oxidation treatment of the surface of Cu substrate. Best electric parameters for the device are as follows: rectifying ratio = 14; threshold potential difference = 0,61 V; saturation current = 2,5 .A . cm -2 ; barrier height = 0,75 eV; diode ideality parameter = 4,23. Doping of five kinds of quinones [p-benzoquinone (p-BQ), tetrabromo-p-benzoquinone (pTBBQ) tetrachloro-p-benzoquinone (p-TCBQ)) tetrachloro-o-benzoquinone (oTCBQ) 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ)] and 2,5-cyclohexadien-l,4-diylidenedimalodinitrile (TNCR) in thin films of polyphthalocyanine affected electrocharacteristics in some cases. The diode ideality parameter decreases to 2,17 at 0,90. 1 0-6 mol . cm-' of pTBBQ, and the rectifying ratio increases to about fourteen times by doping p-TBBQ and p-TCBQ. The doped device shows a rectifying response up to 1 kHz.
A lecithin-type macromonomer 1 was synthesized from natural egg phosphatidylcholine (lecithin). The macromonomer has an olefinic polymerizable group at the hydrophilic site, and is characterized by its chemical structure resembling lecithin. It could be polymerized in a liposome system by UV irradiation, giving polymers with a maximum molecular weight of 98000. Polymers with molecular weights above 48000 form thin and flexible membranes with a few 10 pm in thickness. The polymers can also be redispersed in water and the liposomes can be reconstituted.
Biomembranes consist mainly of phospholipids and proteins. In this study, a new amino lysolecithintype macromer was designed and synthesized, for the preparation of thin membranes that would be similar to biomembranes. This macromer is an artificial phospholipid having two functional groups, a vinyl group to reinforce the membrane and an amino group to introduce the polypeptide chain. It forms small liposomes of 100 nm in the diameter in water. The macromer was not vinyl-polymerized as a liposome in itself, but was copolymerized in the presence of N, N-dimethylacrylamide. Polypeptide chains could be introduced to the vinyl polymerized copolymer by NCA of ƒÁ-benzyl-L-glutamate. The peptide-grafted copolymer was also capable of forming liposomes in water.
Vesicle-forming catalysts, N-{1-[(3-acety1-4-didodecylcarbamoy1-2-thiazolidinyl) manno-tetrahydroxybutyl] carbonyl}-L-histidine and-L-histidyl-L-alanine, and micelle-forming catalysts , N-were designed as hydrolase models. The effects of reaction environment on catalytic activity were examined by the stereoselective hydrolysis of p-nitrophenyl N-benzyloxycarbonyl-L-(or D-phenylalaninate in the absence or presence of cholesterol and/or glycolipids , 3-acetyl-2-(D-manno-pentahydroxypenty1)-4-dodecylcarbamoyl-or-didodecylcarbamoyl-thiazolidine. The vesicle-forming catalyst as well as micelle-forming catalyst assisted by vesicle-forming glycolipid showed superior stereorecognition of chiral substrates compared to the micelle-forming catalyst itself. Stereoselectivity increased by the addition of cholesterol. The above findings are discussed in relation to the environment catalysts function.
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