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21.
Hua-Hua Wang Yi-Yu Jiang Mian HR Mahmood Hai-Yang Liu Herman H.Y. Sung Ian D. Williams Chi K. Chang 《中国化学快报》2015,26(5):529-533
Tetrakis(alloxycarbonyl)porphyrin and its β-octafluoro-substituted derivatives were synthesized via Lindsey method and transformed to their zinc complexes.Single crystal X-ray structures of corresponding Zn(Ⅱ) porphyrins revealed that β-octafluorination will give more compactness of porphyrin moieties in the crystal structure owing to the hydrogen bonding interactions involving β-fluorine atoms.An unusual six-coordinated Zn(Ⅱ) was found via intramolecular coordination of oxygen atom of meso-substituents with central Zn(Ⅱ). 相似文献
22.
One-pot reaction between enaminocarbonyl compounds derived from six-membered 1,3-diketones and substituted benzylamines, and electron-deficient acetylenic esters in the presence of triphenylphosphine lead to alkyl 2-(1-benzyl-6,6-dimethyl-2,4-dioxo-2,3,4,5,6,7-hexahydro-1H-indol-3-yl)acetate derivatives in good yields. 相似文献
23.
Nga-Chun Ng Mian HR Mahmood Chi-K.Chang Hai-Yang Liu Fei Yam Lam-Lung Yeung Chi-K.Chang 《中国化学快报》2014,25(4):571-574
A series of N-base appended corroles and their manganese complexes were synthesized and their binding constants with three different nitrogenous ligands, triethylamine, N-methylimidazole and pyridine, were evaluated by spectroscopy. Kinetic studies indicated that the presence of appended N- donor ligands may cause a significant enhancement of the rate of oxygen atom transfers (OAT) from (oxo)manganese(V) corrole to alkene, and the stronger axial ligand binding has impact on the rate of the oxidation reaction. Turnover frequency (TOF) for the catalytic oxidation of alkenes by appended manganese corroles varies with the following ligand order: acetamido 〈 pyridyl 〈 imidazolyl. The influence of the external axial ligands on the catalytic epoxidation was investigated by using appended acetamido manganese corrole as catalyst, with the results revealing that N-methylimidazole gave the best enhancement on the yields of total oxidation products among the investigated nitrogenous ligands. 相似文献
24.
The regioselective hydrolysis of ketenimines derived from NH-acids, such as 2,2,2-trichloro-N-phenylacetamide or ethyl-2-anilino-2-oxoacetates and acetylenic esters in the presence of tert-butyl isocyanide in a THF/H2O system (1/1) without any catalysis leads to a diastereomeric mixture of dialkyl 2-[(tert-butylamino)carbonyl]-3-[(2,2,2-trichloroacetyl)anilino]succinates and dialkyl 2-[(tert-butylamino)carbonyl]-3-[2-ethoxy-2-oxoacetyl)anilino]-succinates in good yields. Dynamic NMR effects were observed in the
13C NMR spectra of diethyl 2-[(tert-butylamino)carbonyl]-3-[(2,2,2-trichloroacetyl)anilino]succinate as a result of restricted rotation around the N-aryl single bond. The free energy of activation (ΔG
#) for this process is 37.9 kJ mol−1 which leads to an observable atropisomerism.
Correspondence: Dr. Farough Nasiri PhD, Department of Chemistry, Faculty of Sciences, University of Kurdistan, P.O. Box 66315-416,
Sanandaj, Iran. 相似文献
25.
A. Bahraminasab M. Sadegh Movahed S. D. Nasiri A. A. Masoudi Muhammad Sahimi 《Journal of statistical physics》2006,124(6):1471-1490
We carry out an exact analysis of the average frequency ν+
αxi
in the direction x
i
of positiveslope crossing of a given level α such that, h(x, t) − = α, of growing surfaces in spatial dimension d. Here, h(x, t) is the surface height at time t, and is its mean value. We analyze the problem when the surface growth dynamics is governed by the Kardar-Parisi-Zhang (KPZ) equation without surface tension, in the time regime prior to appearance of cusp singularities (sharp valleys), as well as in the random deposition (RD) model. The total number N
+ of such level-crossings with positive slope in all the directions is then shown to scale with time as t
d/2 for both the KPZ equation and the RD model.
PACS number(s): 52.75.Rx, 68.35.Ct 相似文献
26.
Solvent‐free one‐pot synthesis of 2,2′‐dithioxo‐[5,5′]bithiazolidinylidene‐4,4′‐dione (birhodanine) derivatives from the reaction of primary amines and carbon disulfide in the presence of dimethyl acetylene dicarboxylate has been reported. 相似文献
27.
Issa Yavari Hoorieh Djahaniani Farough Nasiri 《Monatshefte für Chemie / Chemical Monthly》2004,11(1):543-548
The 1:1 reactive intermediate generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylates was trapped by fairly strong NH-acids such as carbazole, indole, or pyrrole to yield highly functionalized 1-azadienes and ketenimines. 相似文献
28.
A novel bis-diol monomer, 3,3'-bis-(2-hydroxyethyl)-2,2'-dithioxo-[5,5']bithiazolidinylidene-4,4'-dione, was prepared in a one-pot three component reaction and used in a polyesterification reaction with various aromatic dicarboxylic acids using tosyl chloride/dimethylformamide/pyridine system as a condensing agent in order to generate a series of new polyesters. The prepared polyesters were characterized by FTIR spectroscopy and elemental analysis. In the next part, a series of polyester/clay nanocomposites were synthesized through a polyesterification reaction of the synthesized monomer with iso-phthalic acid. Cloisite 30B was used as the filler at different concentrations. Wide-angle X-ray diffraction and transmission electron microscopy studies showed that the organoclay layers are mainly exfoliated in the nanocomposites containing 1 wt % of Cloisite 30B. 相似文献
29.
A magnetic heterogeneous nanocatalyst based on novel rhodium complex is designed. The transfer hydrogenation of ketones with 2‐propanol as hydrogen donor and the rhodium complex as nanocatalyst was achieved. High yields of ketones under mild conditions were obtained from easily available precursors. 相似文献
30.
A heterogeneous nanocatalyst based on a Cu(II) complex containing phosphotungstic acid and N/O‐donor ligands supported on cobalt ferrite nanoparticles was successfully prepared. The synthesized nanocatalyst was characterized using various techniques. The magnetic nanocatalyst was examined as an efficient and synergistic catalyst for ultrafast synthesis of acetaminophen at room temperature and under solventless conditions. The examined synergistic nanocatalyst, which has both Lewis and Brønsted acidic sites, could be easily separated from the reaction system and reused several times without significant loss of its activity. The synthesized acetaminophen was also fully characterized. 相似文献