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11.
The formation constants of the mono-adducts of α-acylcamphorato-copper(II) chelates such as (+)-Cu(facam)2, (?)-Cu(facam)2, (+)-Cu(hfbc)2 and (?)-Cu(hfbc)2 with some chiral Lewis bases were determined spectrophotometrically in benzene. In order to compare the adduct formation constants obtained with the (+)- and (?)-forms, some pairs of chiral Lewis bases such as 1-amino-2-propanol [(R)(?), (S)(+)], 1-(α-naphthyl)ethylamine [(R)(+), (S)(?)], α-phenyl ethylamine [(R)(+), (S)(?)] and also quinine and quinidine were examined as neutral ligands. Although not very pronounced, the effects of combinations obtained for (+)- or (?)-Cu(II) chelates and (+)- or (?)-ligands indicate that formation constants obtained by the formation of adducts with the ligands having different directions of the optical rotation seems to be superior to those with the same direction. 相似文献
12.
Ning GL Li XC Munakata M Gong WT Maekawa M Kamikawa T 《The Journal of organic chemistry》2004,69(4):1432-1434
Phenyl-substituted cyclopentadienes are proved to form phenylated pyrylium cations in the presence of silver(I) perchlorate by insertion of an oxygen atom into the cyclopentadiene-ring. Three phenylated pyrylium compounds, [(Ph(5)C(5)O(+))(ClO(4)(-))](2)(CH(2)Cl(2)) (1), Ag(ClO(4))(H(2)O)(Ph(4)HC(5)O(+)) (ClO(4)(-)) (2), and (Ph(3)H(2)C(5)O(+))(ClO(4)(-)) (3) have been synthesized and characterized. A possible reaction pathway and formation mechanism of the pyrylium cation are proposed and discussed. 相似文献
13.
Hole transfer process in ODNs conjugated with two organic molecules, pyrene (Py) and phenothiazine (Ptz) was investigated with the pulse radiolysis measurements. Monitoring the transient absorption of Py+ and Ptz+, it was shown that the hole transfer rate was dependent on the distance and sequence between Py and Ptz. 相似文献
14.
15.
John S Forsythe David J.T Hill Anestis L Logothetis Tadao Seguchi Andrew K Whittaker 《Radiation Physics and Chemistry》1998,53(6):657-667
The effect of irradiation temperature on the polymer properties was investigated for the fluoroelastomer poly(tetrafluoroethylene-co-perfluoromethylvinyl ether) (TFE/PMVE). TFE/PMVE samples were γ-irradiated to 150 kGy at temperatures ranging from 77 K to 373 K. Analysis of the sol/gel behaviour, tensile properties, and glass transition temperatures indicated that crosslinking commenced in the temperature range 195 to 263 K, for a dose of 150 kGy. The latter temperature was 13 K below the glass transition temperature. Crosslinking remained relatively constant to higher temperatures. Chain scission reactions were found to occur well below the glass transition temperature and increased at higher temperatures. The optimum temperature for the radiation crosslinking of TFE/PMVE, for the temperatures investigated, was 263 K. 相似文献
16.
Noboru Yamazaki Tadao Iguchi Fukuji Higashi 《Journal of polymer science. Part A, Polymer chemistry》1975,13(4):785-795
Polyureas of high molecular weight were obtained by the direct polycondensation reaction of carbon dioxide with diamines at 40°C for several hours under a pressure of carbon dioxide (below 30 atm) by use of diphenyl phosphite in pyridine. Optimal temperature and pressure were 40°C and 20 atm of carbon dioxide. The polycondensation reaction was also affected by solvents and type and amounts of tertiary amines. Pyridine was most effective as tertiary amine and solvent as well. Of the phosphorous compounds used, triaryl phosphites and diphenyl phosphite were most effective, but trialkyl phosphites failed to give polymer. The reaction was assumed to proceed via a carbamyl N-phosphonium salt of pyridine formed by dephenoxylation of phosphites. Similarly, polythioureas were prepared by heating a mixture of carbon disulfide, diamines, and diphenyl phosphite in pyridine at 40°C for 6 hr under nitrogen. 相似文献
17.
The heat of immersion in water was measured at 25°C for three iron(III) oxides using a twin-type microcalorimeter. One of the samples was commercial α-Fe2O3 (sample C) and the other two (samples M and F) were prepared by calcining magnetite and iron(III) hydroxide in air at various temperatures, Tp, from 300 to 700°C. The samples were evacuated at outgassing temperature, To, between room temperature and 500°C at a pressure of 1 × 10?2?2.7 × 10?2N m?2 for 6 h. The heat of immersion, hi(J m?2), of samples C and M increased with an increase in To and showed the maximum hi at To =400°C, while sample F did not show the maximum up to To =500°C. The systematic correlation was not observed between hi and Tp of sample F. The heat of reproduction of the surface hydroxyl group on sample F was approximately estimated as 6.6 × 104 J mole?1 H2O. 相似文献
18.
Masaaki Fujimatsu Tadao Natsuume Hirotaka Hirata Yasuhiko Shirota Shigekazu Kusabayashi Hiroshi Mikawa 《Journal of polymer science. Part A, Polymer chemistry》1970,8(11):3349-3357
Copolymerizations of N-vinylcarbazole with both isobutyl vinyl ether and N-vinyl-pyrrolidone initiated by some organic electron acceptors have been investigated for the purpose of elucidating the propagation mechanism in the charge-transfer polymerization. Copolymerizations of the same system catalyzed by authentic cationic catalysts have also been made for comparison. The results indicate that the propagation mechanism of the charge-transfer polymerization studied is catio ie. 相似文献
19.
Yasushi OgawaMasahito Toyama Michinori KarikomiKazuo Haga Tadao Uyehara 《Tetrahedron letters》2003,44(10):2167-2170
Both enantiomers of (P)-(+)-2- and (M)-(−)-2-acetoxy-11,14-dimethyl[5]helicenes 8 were synthesized by asymmetric aromatic oxy-Cope rearrangement of the corresponding chiral bridged bicyclic compounds, which were obtained by enzymatic resolution. The absolute configurations of 8 were assigned by their circular dichroism spectra. 相似文献
20.
Although methanolysis of [α-(trimethylsilyl)benzyl]ferrocene (I) and [p-methyl-α-(trimethylsilyl)benzyl]ferrocene (II) in the presence of anhydrous ferric chloride merely gave α-ferrocenylbenzyl methyl ether (III) and p-methyl-α-ferrocenylbenzyl methyl ether (IV), respectively, acid-catalyzed methanolysis of (I) and (II) in the presence of an equimolar amount of (III) or (IV) afforded 1,2-diferrocenyl-l,2-diarylethanes. It is suggested that one electron oxidation of [α-(trimethylsilyl)benzyl]ferrocene by α-ferrocenylbenzyl cation generated from α-ferrocenylbenzyl methyl ether, and subsequent methanolysis of the resulting substituted ferricenium ion may occur to give the two species of α-ferrocenylbenzyl radical, which in turn undergo an approximately statistical coupling. 相似文献