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41.
42.
A direct preparative route to benzoyltrimethylsilane has been found by the reaction of benzoyl chloride with hexamethyldisilane in the presence of a specified palladium(II) complex as catalyst. 相似文献
43.
Bendazzoli Gianni L. Raimondi Mario Garetz Bruce A. George Thomas F. Morokuma Keiji 《Theoretical chemistry accounts》1977,44(4):341-350
Semiclassical calculations are carried out by two methods for the problem of collision-induced predissociation of electronically excited I2. The first method is that of surface-hopping with the Landau-Zener model. The second method is similar to surface-hopping, except that analytic continuation of the adiabatic potential energy surfaces replaces the Landau-Zener model. Results of the calculations by the two methods compare favorably with each other and with experiment. The possible advantages of the second method are discussed.Camille and Henry Dreyfus Teacher-Scholar, Alfred P. Sloan Research Fellow. 相似文献
44.
Leesajakul W Nakano M Taniguchi A Handa T 《Colloids and surfaces. B, Biointerfaces》2004,34(4):253-258
Cubosomes are novel dispersed nanoparticles with bicontinuous cubic phases of monoolein in their interior. We investigated their disintegration process in plasma by in vitro and in vivo studies. Cubosomes were incubated with whole plasma or plasma components such as HDL, LDL, and albumin. The lypolysis study indicated lipolytic activity of whole plasma towards cubosomes. Gel filtration chromatography revealed that HDL, LDL and albumin interacted with cubosomes. HDL affected cubosomes’ integrity and gave rise to smaller particles which contained the components of both cubosomes and HDL. Upon incubation with LDL, cubosomes fused with LDL. Albumin was shown to take up monoolein out of the particles. Cubosomes were disintegrated by whole plasma as a result of the interaction with plasma components. It was concluded that in vivo observation of a long circulation time of a hydrophobic substance in cubosomes was due to the sustained behavior of cubosome remnant particles. 相似文献
45.
The partial molar free energy, enthalpy, and entropy of oxygen in niobium oxides with ratios from 2.47 to 2.50 were measured with a galvanic cell in the temperature range from 1084 to 1325 K. The partial molar enthalpies of oxygen of the Nb2O5?x and V phases were observed to be nearly independent of composition, indicating the presence of only weak interactions between defects. The value of the slope for the plots of log x in Nb2O5?x against log PO2 was observed to be which is interpreted in terms of a defect structure involving both singly ionized and doubly ionized oxygen vacancies. The previously proposed phase diagram in the vicinity of Nb2O5?x was confirmed by the present emf measurements. 相似文献
46.
Five routes to stable chlorins bearing 0 or 1 meso substituents have been investigated, among which reaction of a 9-bromo-1-formyldipyrromethane and 2,3,4,5-tetrahydro-1,3,3-trimethyldipyrrin proved most effective. Application of this route afforded metallochlorins [Cu(II), Zn(II), and Pd(II)] including the chlorin lacking any β-pyrrole and meso substituents. 相似文献
47.
Various computational approaches, using molecular mechanics (Amber), semiempirical (AM1), density functional (B3LYP), and various ONIOM methods, have been comparatively investigated for the structure of Escherichia coli NifS CsdB protein. The structure of the entire monomer containing 407 amino acid residues and 579 surrounding water molecules has been optimized. The full geometry optimization in the "active site-only" approach (including only active site atoms) has been found to give the largest root-mean-square (RMS) deviation from the X-ray structure; a much better agreement has been achieved by keeping the atoms leading to the backbones of some amino acids frozen in their positions in the X-ray structure. The best agreement has been attained by including the surrounding protein in the calculations using the two-layer ONIOM (B3LYP:Amber) approach. The results presented in this study conclusively demonstrate the importance of the protein/active-site interaction on the active-site structure of the enzyme. The present theoretical study represents the largest system studied at the ONIOM level to date, containing 7992 atoms, including 84 atoms in the QM region and rest in the MM region. 相似文献
48.
49.
Hirai A Matsui A Komatsu K Tanino K Miyashita M 《Chemical communications (Cambridge, England)》2002,(17):1970-1971
A highly regio- and stereoselective alpha-methylation reaction of gamma,delta-epoxy-alpha,beta-unsaturated esters was achieved by using a Me2Zn-CuCN reagent. 相似文献
50.
Takaki K Itono Y Nagafuji A Naito Y Shishido T Takehira K Makioka Y Taniguchi Y Fujiwara Y 《The Journal of organic chemistry》2000,65(2):475-481
Three-component coupling of acylphosphonates and two carbonyl compounds leading to beta-hydroxyphosphonates has been achieved with low-valent samariums. Thus, acylphosphonates reacted with aldehydes in the presence of semicatalytic amounts of samarium metal or SmI(2) to give acyloxyphosphonates in good yields. The second coupling reaction of the acyloxyphosphonates with aldehydes or ketones promoted by SmI(2) afforded beta-hydroxyphosphonates instead of olefins. Moreover, these two reactions could be carried out in one pot. 相似文献