(Ss)-3-(p-Tolylsufinyl)-2-furaldimine was synthesized, and condensation of the chiral furaldimine with lithium ester enolates has been examined. The product distribution of the reaction is dependent upon reaction conditions and on the kind of the substituent placed on the esters. Disubstituted ester enolate resulted in the exclusive formation of (4R)-beta-lactam, while unsubstituted, tert-butyl ester enolate preferentially gave (3R)-beta-amino ester. With the monosubstituted ester enolates, the condensation afforded (4R)-beta-lactams and/or (3R)-beta-amino esters as major products. This method has been applied to an efficient route to chiral furyl beta-lactams. 相似文献
The thermal dehydration reactions of two kinds of copper(II) formate dihydrate, which differ in origin and preparation history, have been investigated by means of TG, DTA and DSC. The kinetics of isothermal dehydration were studied by weight loss, and the difference in kinetic behavior between these two samples was related to the difference in origin and preparation history. On the whole, the dehydration mechanisms of these two samples were found to be phase boundary controlled contracting interface reactions. 相似文献
The thermal dehydration of some rare earth metal formate dihydrates were studied by means of thermogravimetry, differential thermal analysis and differential scanning calorimetry.The dehydration took place successively as a one step reaction for all of the formate dihydrates examined. The reaction order of dehydration was found to be for all of the salts examined, which indicated that the rate of dehydration was controlled by a chemical process at a phase boundary.The values of the activation energy, frequency factor and the enthalpy change of dehydration for all of the dihydrates were 108–142 kJ mole?1, 1016–1017 min?1 and 109–147 kJ mole?1, respectively.Both the temperature at which the dehydration occurred and the enthalpy change increased as the reciprocal of the radius of the metallic ion increased. 相似文献
The general and efficient silylation of aryl halides has been developed utilizing triethoxysilane and a rhodium catalyst. The substrate scope is broad and includes ortho-, meta-, and para-substituted electron-rich and -deficient aryl iodides. In addition, the silylation of aryl bromides and fluoroalkanesulfonates proceeded in the presence of tetra-n-butylammonium iodide. 相似文献
Anionic copolymerizations of acrylonitrile (monomer 1) with β-propiolactone (monomer 2) and the structures of the resulting copolymers were studied. The copolymerization with sodium cyanide in N,N-dimethylformamide gave copolymers of the structure I containing acid anhydride linkage in the molecular chains, with the monomer reactivity ratios, r1 = 1.20, r2 = 0.00. The copolymerization with potassium hydroxide gave either copolymers of the structure II (r1 = 0.00, r2 = 3.64 at 30°C; r1 = 0.00, r2 = 5.00 at 40°C) in N,N-dimethylformamide or only β-propiolactone homopolymer in toluene. 相似文献
The structure of Cu2Fe2Ge4O13, previously thought to be CuFeGe2O6, has been determined from single-crystal X-ray diffraction data to be monoclinic, P21/m, a=12.1050(6), b=8.5073(4), c=4.8736(2) Å, β=96.145(1)°, Z=2, with R1=0.0231 and wR2=0.0605. The unique structure has an oligomer of four germanate tetrahedra, cross-linked laterally by square-planar copper ions, joined end-to-end by a zigzag chain of edge-sharing iron oxide octahedra. Running along the a-direction the metal oxide chain consists of alternating Cu-Cu and Fe-Fe dimers. A hypothetical series of homologous structures (Cun−2Fe2GenO3n+1 with n=3,4,…,∞) with different length germanate oligomers is proposed, where as n increases, the infinite chain of the CuGeO3 is approached. In this context, Cu2Fe2Ge4O13 is viewed as being built from blocks of CuGeO3 and the Fe oxide chains. This material has significance to the study of low-dimensional mixed-spin systems. 相似文献
The first isolation and spectroscopic characterization of the mononuclear hydroperoxo-iron(III) complex [Fe(H(2)bppa)(OOH)](2+) (2) and the stoichiometric oxidation of substrates by the mononuclear iron-oxo intermediate generated by its decomposition have been described. The purple species 2 obtained from reaction of [Fe(H(2)bppa)(HCOO)](ClO(4))(2) with H(2)O(2) in acetone at -50 degrees C gave characteristic UV-vis (lambda(max) = 568 nm, epsilon = 1200 M(-1) cm(-1)), ESR (g = 7.54, 5.78, and 4.25, S = (5)/(2)), and ESI mass spectra (m/z 288.5 corresponding to the ion, [Fe(bppa)(OOH)](2+)), which revealed that 2 is a high-spin mononuclear iron(III) complex with a hydroperoxide in an end-on fashion. The resonance Raman spectrum of 2 in d(6)-acetone revealed two intense bands at 621 and 830 cm(-1), which shifted to 599 and 813 cm(-1), respectively, when reacted with (18)O-labeled H(2)O(2). Reactions of the isolated (bppa)Fe(III)-OOH (2) with various substrates (single turnover oxidations) exhibited that the iron-oxo intermediate generated by decomposition of 2 is a nucleophilic species formulated as [(H(2)bppa)Fe(III)-O*]. 相似文献
Charge-discharge capacity and cyclicity of lithium ion battery (LIB) was evaluated in which 15Li2O·10Fe2O3·xSnO2·5P2O5·(70–x)V2O5 glass (x?=?0 and 20 in mol%, abbreviated as xLFSPV) was used as a cathode. A local structure of xLFSPV glass before and after charging was investigated by 57Fe- and 119Sn-Mössbauer spectroscopies. 57Fe-Mössbauer spectrum of xLFSPV glass with ‘x’ of 20 was composed of a doublet with isomer shift (δ) of 0.35±0.02 mm s???1 and quadrupole splitting (Δ) of 0.88±0.03 mm s???1 due to distorted FeIIIO4 tetrahedra. 119Sn-Mössbauer spectrum of this glass consisted of a doublet with δ of 0.08±0.01 and Δ of 0.52±0.01 mms???1 due to distorted SnVIO6 octahedra. After discharging the battery from 4.5 to 1.0 V, larger δ of 0.40±0.03 mm s???1 and Δ of 0.94±0.04 mm s???1 were obtained, indicating that both iconicity of Fe-O bonds and local distortion of FeIIIO4 tetrahedra were increased. On the contrary, identical δ of 0.09±0.01 mm s???1 and Δ of 0.50±0.01 mm s???1 were observed in the 119Sn-Mössbauer spectrum of 20LFSPV glass after the discharge, indicating that chemical environment of SnIVO6 octahedra was not affected after the discharge. Charge-discharge curve of LIB containing 20LFSPV glass as a cathode active material recorded under the current density of 8.3 mA g???1 (0.011 mA cm???2) between 1.0 and 4.5 V showed a large initial charge capacity of 431.1 mAh g???1 and discharge capacity of 382.3 mAh g???1, respectively. These results indicate that 20LFSPV glass could be a new cathode active material for LIB. 相似文献