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21.
A hybrid approach combining energy density analysis with the interaction energy decomposition method
We propose a new analysis technique for characterizing molecular interactions that combines an energy decomposition scheme, such as the Kitaura-Morokuma decomposition method, with energy density analysis, which partitions the total energy of the system into atomic contributions. The combined scheme, termed Interaction-EDA, enables us to estimate the local contribution of interaction energy components, such as electrostatic, exchange, polarization, and charge transfer. The evaluation of the local interaction energy is rather important in large systems. For a numerical assessment, the Interaction-EDA method is applied to the process of CO adsorption on Si(100) - (2 x 1) surface. 相似文献
22.
Shin-ichi Naya 《Tetrahedron》2004,60(23):4953-4958
The synthesis and properties of a novel type of 7,7-bis(heteroazulen-3-yl)-8,8-dicyano-1,4-quinodimethanes (9a-c) are studied. The synthetic method is based on a TFA-catalyzed electrophilic aromatic substitution on the heteroazulenes with 4-(dicyanomethyl)benzaldehyde to afford the corresponding methane derivatives, followed by oxidative hydrogen abstraction with DDQ. The polarization of 9a-c is evaluated by the inspection of their 13C NMR and IR spectra. Based on the investigation of the UV-Vis spectra of 9a-c and protonated cations 10a-c, conformational changes of the heteroazulene-moiety and (dicyanomethyl)phenyl group are suggested. In the CV measurements of 9a-c, two reversible reduction waves are observed, indicating the stabilizing ability of heteroazulenes toward the corresponding radical and anion species. Furthermore, 9a-c exhibit two irreversible oxidation waves, which suggest a conformational change in the radical cation during the redox process. The conformational change is rationalized on the basis of the MO calculations. 相似文献
23.
Animal fibrous proteins (AFPs) such as egg-shell membrane (ESM), chicken feather (CF), wool, silk, or elastin are an intricate
network of stable and water-insoluble fibers with high surface area and are abundant bioresources. Every AFP tested was found
to accumulate gold-cyanide ion from aqueous solutions in high yield, depending on pH and some other parameters. Gold-cyanide
ion is adsorbed by AFP at low pH range, with maximum binding observed at approx pH 2.0. Under the certain conditions, gold-cyanide
ion was accumulated up to 8.6, 7.1, 9.8, 2.4, and 3.9% of dry weight on ESM, CF, wool, silk, and elastin, respectively. In
the case of ESM, it was found that ESM removed gold-cyanide ion almost quantitatively and almost all the gold uptake by ESM
was easily desorbed with 0.1M NaOH. ESM can be used repeatedly for the process of gold adsorption-desorption. The gold-biosorptive capacity of ESM that
was chemically modified with glutaraldehyde was higher than that of control. In column procedure, ESM packed on column removed
gold-cyanide ion from the dilute aqueous solution to extremely low concentrations (nondetectable concentration of below 1
ppb) 相似文献
24.
Toshiyuki Uryu Toshiyuki Seki Tokiji Kawamura Akashi Funamoto Kei Matsuzaki 《Journal of polymer science. Part A, Polymer chemistry》1976,14(12):3035-3044
The stereoregularity of polystyrene prepared by anionic polymerization was determined by means of 13C-NMR spectroscopy. The stereoregularity changed with such polymerization conditions as catalyst, solvent, and temperature. Sodium naphthalene as catalyst gave a syndiotactic-rich polystyrene of 66–68% syndiotactic dyads independently of solvent and temperature, while potassium and cesium naphthalenes as catalyst produced polystyrenes with different stereoregularities ranging from syndiotactic-rich to isotactic-rich configurations, depending on solvent and temperature. The mechanism of anionic polymerization which caused the difference in stereoregularity was discussed from the viewpoint of growing ionic species. 相似文献
25.
Treatment of alkenyl and aryl tellurides with Grignard reagents in the presence of NiCl2(PPh3)2, NiCl2(Ph2PCH2CH2CH2PPh2), or CoCl2(PPh3)2 as catalyst affords the cross-coupling products together with the homo-coupling products of the tellurides in good to moderate yields under mild conditions. 相似文献
26.
Shin-ichi Hirano Toshinobu Yogo Wataru Sakamoto Seiji Yamada Tomoyuki Nakamura Tomoe Yamammto Hiroyuki Ukai Kouichi Banno Tomoko Nakafuku Yukari Ando 《Journal of Sol-Gel Science and Technology》2003,26(1-3):35-41
Nano sized crystalline particles/polymer hybrids were synthesized form designed metal-organic precursors. The newly developed method is composed of the synthesis of organic matrix by polymerization and the in situ nucleation and growth of crystalline oxide particles in the organic matrix below 100°C. The design of metal-organic precursor modified with polymerizable ligand and the selection of reaction conditions does influence the size and crystallinity of ceramic particles in organic matrix. The nano-sized magnetic particle/polymer hybrid exhibits the interesting feature of superparamagnetism and quantum size effect. The crystalline particles of BaTiO3/, PbTiO3/, and KNbO3/polymer hybrids behave to be dielectric and show the typical electro-rheological behavior. 相似文献
27.
Masahiro Manabe Asako Tokunaga Hideo Kawamura Hajime Katsuura Masaki Shiomi Koichi Hiramatsu 《Colloid and polymer science》2002,280(10):929-935
In the micellar solution of SDS, the partition coefficient (Kx) of following branched alkanols at infinite dilution was determined by applying a differential conductivity method: the alkanols used were i-CmH2m+1OH (m=4-9, i=1-5) in which the position of OH group (i) shifts from an end to the center of a hydrocarbon chain. The method provides two significant quantities, d!/dXam and dCsf/dCaf in addition to Kx. The following results have been obtained. (1) The dependence of Kx on i indicates that the hydrophobicity of alkanol is weakened with increasing i, whereas the increase in m strengthens the hydrophobicity. (2) The degree of counterion disossiation of micelles (!) is accelerated by the solubilized alkanols in micelles (mole fraction: Xam) and the acceleration rate, d!/dXam (=0.17), depends on neither m nor i. (3) In the bulk water, the monomerically dissolved alkanols (concentration: Caf) depresses the concentration of free monomer surfactant (Csf), and the depressing rate, dCsf/dCaf, in micellar solution is identical with the corresponding quantity, ((CMC/(Ca)o at CMC. 相似文献
28.
Fujii H Hirano N Uchiro H Kawamura K Nagase H 《Chemical & pharmaceutical bulletin》2004,52(6):747-750
7beta-Carbamoyl-4,5alpha-epoxymorphinans 5 were stereoselectively synthesized from the 7alpha-carboxylate intermediate 3 in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and amines under reflux conditions in mesitylene via a novel and reactive gamma-lactone 7. These were the first examples of the stereoselective syntheses of 7beta-substituted 4,5alpha-epoxymorphinans. The mechanism of the reaction process was elucidated as follows: 1) epimerization of 7alpha-carboxylate 3, 2) intramolecular lactonization of 7beta-carboxylate 6, and 3) aminolysis of the resultant gamma-lactone 7. The aminolysis of the isolated reactive gamma-lactone 7 with allylamine and the alcoholysis with MeOH in the presence of NaBH(4) proceeded at room temperature. The gamma-lactone 7 can be a useful intermediate for the preparation of 7beta-substituted 4,5alpha-epoxymorphinans that would be potent selective delta opioid receptor ligands. The stereoselective syntheses of the 7alpha-carbamoyl-4,5alpha-epoxymorphinans 9 from 7alpha-carboxylate 3 via 7alpha-carboxylic acid were also successful. 相似文献
29.
[reaction: see text] The Sc(OTf)3/FERRODIOL (2) complex was prepared at -78 degrees C in CH2Cl2 in the presence of 2,6-lutidine and MS 4A. The chiral scandium Lewis acid-catalyzed asymmetric Diels-Alder reaction of cyclopentadiene (3) with 3-acyloxazolidin-2-ones (4) effectively produced the adduct (5) in a high yield with good selectivity, i.e., endo/exo = 90:10 up to 91% ee (endo). 相似文献
30.
Kiyoharu Nishide Shin-ichi Ohsugi Tetsuo Miyamoto Kamal Kumar Manabu Node 《Monatshefte für Chemie / Chemical Monthly》2004,135(2):189-200
Summary. Development of new odorless thiols (dodecanethiol, 4-n-heptylphenylmethanethiol, 4-trimethylsilylphenylmethanethiol, 4-trimethylsilylbenzenethiol) and an odorless sulfide (1-methylsulfanyldodecane) and their applications to dealkylation, Michael addition, Swern oxidation, and Corey-Kim oxidation are described. 相似文献