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81.
Masahiro Sekiya Takeshi Noro Toshikatsu Koga Shiro L. Saito 《Journal of computational chemistry》2010,31(3):497-499
Developed and reported are compact yet efficient correlating basis sets for the 57La and 89Ac atoms, missing in the literature. Good performance of these correlating sets is exemplified in molecular applications to diatomic oxides and fluorides. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 相似文献
82.
A comparative study on chemical conversion of cellulose between the batch-type and flow-type systems in supercritical water 总被引:1,自引:0,他引:1
Microcrystalline cellulose (avicel) was treated in supercritical waterusing batch-type and flow-type systems. The flow-type system made it possibletoshorten the heating, treating and cooling times, compared with the batch-typesystem. As a result, the flow-type system was able to liquefy avicel withoutproducing any supercritical water-insoluble residue. Although hydrolyzedproducts such as glucose and fructose, and pyrolyzed products such aslevoglucosan, 5-hydroxymethyl furfural, erythrose, methylglyoxal,glycolaldehydeand dihydroxyacetone were found in common from the water-soluble portiontreatedby both systems, the flow-type system gave a water-soluble portion with morehydrolyzed and less pyrolyzed products, together with water-solubleoligosaccharides consisting of cellobiose to cellododecaose and theirdecomposedproducts at their reducing end of glucose, such as[–glucopyranosyl]1–11 –levoglucosan,[–glucopyranosyl]1–11 –erythrose and[–glucopyranosyl]1–11 –glycolaldehyde. Inaddition, the precipitates of polysaccharides were recovered after 12h setting of the water-soluble portion. These results indicatedthat the flow-type system can hydrolyze cellulose with minimizing pyrolyzedproducts. On the other hand, the batch-type system resulted in a higher yieldof the pyrolyzed products due to the longer treatment, but a higher yield ofglucose due possibly to the higher pressure and concomitantly higher ionicproduct of water. Based on these lines of evidence, the process to increase theyield of the sugar is discussed under supercritical water treatment. 相似文献
83.
Matsumoto T Kominami T Ueda K Sugimoto T Tada T Noguchi S Yoshino H Murata K Shiro M Negishi E Toyota N Endo S Takahashi K 《Inorganic chemistry》2002,41(18):4763-4769
The 2:1 charge-transfer (CT) salts (1(2).FeBr(4) and 1(2).GaBr(4)) of ethylenedithiotetrathiafulvalenoquinone-1,3-dithiolemethide (1) with FeBr(4)(-) and GaBr(4)(-) counteranions were obtained as needle crystals, whose structures are almost the same as each other. The 1 molecules form a one dimensionally stacked column with alternation of their molecular axis direction, while the counteranions are aligned in parallel with the 1-stacked columns with the direction of their distorted-tetrahedral geometry maintained. The room-temperature electrical conductivities measured on the single crystals of 1(2).FeBr(4) and 1(2).GaBr(4) were 4.6 and 2.1 S cm(-1), respectively. From the temperature dependences of their electrical conductivities in both cases the electrical conducting properties were metallic between ca. 170 and 300 K, but below ca. 170 K converted to be semiconducting and continued till 5 K, although the activation energies are very small (4-10 meV). For 1(2).FeBr(4) very weak and antiferromagnetic interaction occurred between the d spins of FeBr(4)(-) ions in the temperature range of ca. 1-300 K. However, below ca. 15 K the ferromagnetic interaction was reversely preferential possibly by participation of the pi spin of 1. 相似文献
84.
An insoluble and assembled catalyst of palladium and a non-cross-linked amphiphilic polymer were developed. In the presence of 50-500 ppm mol equiv of catalyst, the Suzuki-Miyaura reaction proceeded efficiently under organic solvent-free conditions. The catalyst was reused 10 times without any decrease in activity and was recycled without any special treatment.[structure: see text] 相似文献
85.
[reaction: see text] D-Mannono-1,4-lactone was efficiently converted into L-ribose in eight steps. A key step of this synthesis is the cyclization of a gamma-hydroxyalkoxamate under Mitsunobu conditions. It is noteworthy that the O-alkylation product was obtained in 94% yield and that none of the N-alkylation product was detected in this cyclization. 相似文献
86.
Krokovny P Abe K Abe K Abe T Adachi I Ahn BS Aihara H Akatsu M Asano Y Aso T Aulchenko V Aushev T Bakich AM Ban Y Banas E Bay A Bedny I Behera PK Bizjak I Bondar A Bozek A Bracko M Brodzicka J Browder TE Casey BC Chang P Chao Y Chen KF Cheon BG Chistov R Choi SK Choi Y Danilov M Dong LY Drutskoy A Eidelman S Eiges V Enari Y Everton CW Fang F Fukunaga C Gabyshev N Garmash A Gershon T Golob B Gordon A Guo R Haba J Hanagaki K Handa F Harada Y Hayashii H Hazumi M Heenan EM Higuchi T Hinz L Hojo T 《Physical review letters》2002,89(23):231804
We report the first observation of a B meson decay that is not accessible by a direct spectator process. The channel B(0)-->D(+)(s)K- is found in a sample of 85 x 10(6) BB; events, collected with the Belle detector at KEKB, with a branching fraction B(B(0)-->D(+)(s)K-)=(4.6(+1.2)(-1.1)+/-1.3) x 10(-5). We also obtain evidence for the B0-->D(+)(s)pi(-) decay with branching fraction B(B0-->D(+)(s)pi(-))=(2.4(+1.0)(-0.8)+/-0.7) x 10(-5). This value may be used to extract a model-dependent value of |V(ub)|. 相似文献
87.
Kodera M Tachi Y Kita T Kobushi H Sumi Y Kano K Shiro M Koikawa M Tokii T Ohba M Okawa H 《Inorganic chemistry》2000,39(2):226-234
Two sterically hindered tris-pyridyl methane ligands, tris(6-methyl-2-pyridyl)methane (L1) and bis(6-methyl-2-pyridyl)pyridylmethane (L2), are newly synthesized. Under aerobic conditions, Ln (n = 1 or 2) reacts with CuX2 (X = Cl or Br), oxygenated at the methine position to LnOH or LnOMe. The former alcoholate ligand creates trinuclear Cu(II) complexes [Cu3(X)(LnO)3](PF6)2 [(X, n) = (Br, 1) 1, (C1, 1) 2, (Br, 2) 3, or (C1, 2) 4] in which the alkoxide oxygen atoms bridge copper centers. The crystal structures of 1-4 are presented along with their magnetic susceptibility data. The weak antiferromagnetic coupling between the Cu(II) centers in this trinuclear arrangement is due to weak interaction of the magnetic orbitals (dz2) which are oriented along three alternate sides in a hexagon of the Cu3O3 core in 1-4. Under anaerobic conditions, L1 reacts with CuBr2 to form a square pyramidal complex [CuL1Br2] (9) with the ligand facially capping. [Cu(Br)2(L1OMe)] (10) was obtained after the suspension of 9 in MeOH was stirred under air for 48 h. In the presence of cyclohexene, 9 is converted to [Cu(Br)(L1)]m (m = 1 or 2) 5 quantitatively to give trans- 1,2-dibromocyclohexane, indicating that Br2 is generated during the reaction. The FAB MS spectrum of [18O]-1 prepared by the reaction of L1 with CuBr2 under 18O2 shows that the ligand of [18O]-1 is L1(18O-.) L1(18OH), L1OCD3, and bis(6-methyl-2-pyridyl) ketone were obtained from reaction of L1 with CuBr2 in CD3OD under 18O2. These results indicate that the origins of the O atom in L1OH and L1OMe are O2 and MeOH, respectively. On the basis of these results, a mechanism of the oxygenation of L1 in the present system will be proposed. 相似文献
88.
The C-S stretching vibrations of 28 aliphatic sulfides including one thiol are summarized, and all of the C-S stretching bands are classified into several groups. An extraordinarily low frequency associated with the ethyl group is discussed briefly. 相似文献
89.
90.
Tsukasa Ikeda Ryoichi Kojin Chul-joong Yoon Hiroshi Ikeda Masao Iijima Kenjiro Hattori Fujio Toda 《Journal of inclusion phenomena and macrocyclic chemistry》1984,2(3-4):669-674
Cyclodextrin (CD) has a hydrophobic cavity which acts like a binding site of an actual enzyme. But enzymatic turnover reaction did not occur in CD-catalyzed reactions. -CD was modified by a histamine group to attach a reactive functional group. -CD-histamine accelerates the hydrolysis of p-nitrophenyl acetate. Catalytic rate constant of this reaction is close to an actual enzyme, -chymotrypsin. Enzymatic turnover reaction is realized with this compound at around neutral pH value. 相似文献