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111.
An efficient synthetic method for the formation of 2,3-dihydro-1H-inden-1-one derivatives through a Ni-catalyzed intramolecular hydroacylation of 2-(prop-2-ynyl)benzaldehydes has been developed. Examination of various nickel and other transition metal catalysts and phosphine ligands showed that the use of Ni(COD)2 catalyst combined with P(i-Pr)3 ligand was the best choice to the success of the present intramolecular hydroacylation. A wide range of functional groups were tolerated, affording the corresponding substituted α-lidene-2,3-dihydro-1H-inden-1-ones in good to high yields with a sole E-selectivity under present reaction conditions. 相似文献
112.
Yoshinori Takahashi 《Zeitschrift für Physik B Condensed Matter》1990,78(2):199-206
We propose a model Hamiltonian for the high temperature superconductivity from the analogy of the BCS model hamiltonian. We seek a possibility of real space electron pairing. It follows then the magnetic exchange interaction is not a source of pairing and we propose a form of pairing interaction from the argument of the broken symmetry of electron number conservation. Based on a variational wave function, the ground state energy of our model is studied. 相似文献
113.
Sumitomo K Mayumi K Minamikawa H Masuda M Asahi T Shimizu T Ito K Yamaguchi Y 《Electrophoresis》2011,32(3-4):448-454
Although polyethylene oxide (PEO) offers several advantages as a sieving polymer in SDS capillary polymer electrophoresis (SDS-CPE), solution properties of PEO cause deterioration in the electrophoresis because PEO in solution aggregates itself, degrades into smaller pieces, and forms polymer-micelle complexes with SDS. We examined protein separation on SDS-CPE with PEO as a sieving matrix in four individual buffer solutions: Tris-CHES, Tris-Gly, Tris-Tricine, and Tris-HCl buffers. The solution properties of PEO as a sieving matrix in those buffers were examined by dynamic light scattering (DLS) and by surface tension. Preferential SDS adsorption onto PEO disturbed protein-SDS complexation and impaired the protein separation efficiency. Substantial adsorption of SDS to PEO was particularly observed in Tris-Gly buffer. The Tris-CHES buffer prevented SDS from adsorbing onto the PEO. Only Tris-CHES buffer achieved separation of six proteins. This study demonstrated efficient protein separation on SDS-CPE with PEO. 相似文献
114.
Yoshinori Takanohashi Narumi Tabata Tomoaki Tanase Sadatoshi Akabori 《Journal of organometallic chemistry》1993,450(1-2):103-108
The reaction of bis(2-bromoethyl)selenium dibromide (1a) with 1,5-hexadiene (2) in methanol or ethanol affords 2,5-bis(alkoxymethyl)tetrahydroselenophene-1,1-dibromides (R = CH3 (3b), R = C2H5 (3c)) via 2,5-bis(bromomethyl)tetrahydroselenophene-1,1-dibromide (3a). The reaction of 1a with 2 in 1-propanol, 2-methyl-1-propanol or 1-butanol in the presence of sodium carbonate gave 2,5-bis(alkoxymethyl)tetrahydroselenophene (R = C3H7 (4a), R = (CH3)2CHCH2 (4b) and R = C4H9 (4c)) via 3a. The ratios of the trans and cis isomers of 3a–3c are 3:2. In addition, the structure of trans-2,5-bis(methoxymethyl)tetrahydroselenophene-1,1-dibromide (trans-3b) was determined by X-ray crystallography. 相似文献
115.
The transient absorption properties of several commercially available TiO2 photocatalysts were investigated by femtosecond diffuse-reflectance spectroscopy. Using femtosecond diffuse-reflectance spectroscopy, the quantities and rates of the initial trapping processes of holes and electrons generated by the photoexcitation of TiO2 photocatalysts were investigated. It was found that the total amounts of trapped electrons for the pure-anatase and pure-rutile TiO2 became smaller with increasing particle size, but increased again when the particles’ diameters were larger than 50 nm. The anatase–rutile mixed TiO2 photocatalysts were found to have smaller amounts of trapped electrons compared with pure-anatase and pure-rutile TiO2 photocatalysts. The lifetimes of trapped holes of various TiO2 photocatalysts were also investigated, and it was found that the lifetimes were proportional to the anatase–rutile mixed ratios. 相似文献
116.
Regio- and diastereoselective reaction of oxygen and sulfur substituted allylic carbanions with aldehydes is described. Either threo or erythro isomer can be obtained predominantly or exclusively by merely choosing an additive. 相似文献
117.
118.
Two diterpenoids, (+)-labda-7,14-dien-13-ol and (+)-manoyl oxide, and one bis(bibenzyl) compound, isomarchantin C, were isolated as the major components from the Taiwanese liverwort Mylia nuda. The spectral evidence is discussed in this paper. In addition, several monoterpenes and sesquiterpenes were also identified by GC/MS. 相似文献
119.
120.
Yoshinori Nagahama 《Zeitschrift fur Physik C Particles and Fields》1986,31(4):583-590
We consider the 2+1 dimensional massive QED and discuss the induced topological term in the one-loop level by using the higher derivative regularization. We show that the higher derivative regularization, which manifestly preserves the parity invariance when the fermion mass vanishes, automatically leads to a nonvanishing topological term in low energies. Although this higher derivative regularization formally violates the local gauge invariance, we propose a systematic way to recover the gauge invariance by adding local counter terms dictated by Ward-Takahashi identities. In practical applications, this regularization is interesting in connection with the discussion of the dynamical origin of the quantum Hall effect. 相似文献