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1.
Aromatic α-bromo ketones and α-iodio ketones can be reduced by bismuth prepared from NaBH4 and BiCl3 in water to their parent ketones in high yields, but aromatic α-chloro ketones should be added to sodium iodide first.  相似文献   

2.
3.

Equimolar copolymerizations of glycolide and L‐lactide were conducted in bulk in the temperature range from 100 to 160°C. The catalytic efficiency of tin(II)2‐ethylhexanoate (SnOct2) and bismuth(III)n‐hexanoate (BiHex3) were compared under identical conditions. Furthermore, four copolymerizations were conducted with bismuth subsalicylate as initiator/catalyst. The isolated copolyesters were characterized by viscosity and SEC measurements, by 1H‐NMR spectroscopy with regard to their composition and with 13C‐NMR spectroscopy with regard to their sequences. BiHex3 proved to be nearly as efficient as initiator as SnOct2 and the sequences were somewhat closer to randomness than those obtained from SnOct2. All copolyesters were amorphous materials soluble in a variety of organic solvents. Chain extension with diisocyanates raised the molecular weights by a factor of 5–7.  相似文献   

4.
Friedel–Crafts acylations of various 3-arylsydnones at the C4 position have been achieved in good yields using 4 equivalents of an alkyl anhydride and 25 mol% each of bismuth triflate and lithium perchlorate in anhydrous acetonitrile at 95 °C. Acylations appear to be faster with arylsydnones bearing electron-donating moieties and sterically unencumbered anhydrides.  相似文献   

5.
 A micro extraction – spectrophotometric procedure is developed for the determination of bismuth in pharmaceutical formulations. The procedure is based on the extraction of tetraiodobismuthate(III) ion paired with benzyltributylammonium cation into chloroform. The application of Nile Blue as internal standard (IS) enabled good analytical performance for micro-scale analysis. The ratio between the absorbances measured at 491 nm (bismuth complex) and at 632 nm (IS) was taken as the analytical signal. The procedure was carried out in Eppendorf tubes, lowering significantly the use of reagents and the volume of organic solvent. In the calibration range up to 60 mgċl−1, the linear regression coefficient was 0.9999, the CV for 15 mgċl−1 and for 50 mgċl−1 Bi were 1.6% and 0.7% respectively. The results obtained in the analysis of pharmaceutical formulations were in good agreement with the results of EDTA titration method. Received November 25, 1999. Revision February 14, 2000.  相似文献   

6.
杜永令  王春明 《中国化学》2002,20(6):596-600
ThecombinationofstrippingvoltammetrywithUPDcanleadtotheimprovementofsensitivity ,selectivi tyandreversibilityforelectroanalyticalpurposeandavoidtheuseoftoxicmercuryastheworkelectrode1andthenanalyticalapplicationshavebeendescribed .2 4 Inthiswork ,wedevelo…  相似文献   

7.
The catalytic activity of metal triflates was investigated in Friedel–Crafts benzoylation under microwave irradiation. Friedel–Crafts benzoylation with benzoyl chloride of a variety of arenes containing electron-rich and electron-poor rings using bismuth triflate under microwave irradiation is described. This method allows the preparation of aryl ketones under solventless conditions in good to excellent yields and short reaction time. Bismuth triflate was easily recovered and reused five times without significant loss of the catalytic activity.  相似文献   

8.
The BiCl3‐catalyzed reaction of pyrroles with electron‐deficient olefins generated the corresponding Michael adducts in high yields.  相似文献   

9.
Two novel complexes, [Bi(III)(S2CNBn Et)3] 1 and [Bi(III)(S2CNPPPy-2)3] 2, were synthesized and characterized by elemental analysis, IR, 1H NMR, 13 C NMR, TG-DTG and X-ray single-crystal diffraction. The structure reveals that complex 1 belongs to the monoclinic system, space group P21/c with a = 11.457(5), b = 17.437(8), c = 33.439(14), β= 98.499(8)o, Z = 4, V = 6607(5)3, Dc = 1.689 g·cm-3, F(000) = 3328, μ= 5.742 mm-1, the final R = 0.0906, w R = 0.1678 and S = 1.032. The structure indicates that complex 2 belongs to the triclinic system, space group P1 with a = 12.608(9), b = 12.622(8), c = 12.49(6), α = 102.652(15), β = 103.013(14), γ = 109.698(10)o, Z = 1, V = 1762.3(19)3, Dc = 1.741 g·cm-3, F(000) = 916, μ = 5.395 mm-1, the final R = 0.048 2, w R = 0.1206 and S =1.046. In the two complexes, each six-coordinated Bi(III) atom adopts a pentagonal pyramidal configuration with six sulfur atoms from three ligands, and the dimmer structures are formed by weak interactions of Bi···S between two molecules. The anticancer activities of the two complexes were studied by evaluating their cytotoxicities against several human cancer cell lines using the MTT assay. Results indicated complex 2 showed moderate cytotoxic effects on the selected cancer cells.  相似文献   

10.
《Analytical letters》2012,45(12):1887-1897
Abstract

The application of bismuth film electrodes to the determination of cobalt by constant current adsorptive stripping potentiometry with exploitation of a catalytic effect is presented. The addition of NaNO2 to the solution containing ammonia buffer and dimethylglyoxime results in a 25‐fold enhancement of the adsorptive stripping potentiometric cobalt signal. Several key parameters of the potentiometric stripping mode were optimized, including the composition of the supporting electrolyte, the stripping current, the accumulation potential, and the accumulation time. The optimized procedure yields favorable and highly stable stripping responses with good precision (RSD=1.4% for a Co concentration of 2 µg L?1), low detection limit (0.07 µg L?1), and good linearity (up to 10 µg L?1, R2=0.998) with a deposition time of 60 s and a stripping current of 10 µA. The method enables the determination of Co in the presence of high excesses of Ni or Zn.  相似文献   

11.
Junmin Zhang 《合成通讯》2013,43(15):2615-2624
Various biologically important perimidine derivatives have been efficiently synthesized in excellent yields from naphthalene‐1,8‐diamine and various ketones in the presence of a catalytic amount of BiCl3.  相似文献   

12.
Bismuth-promoted (1% and 3%) vanadyl pyrophosphate catalysts were prepared by refluxing Bi(NO3)3·5H2O and VOPO4·2H2O in isobutanol. The incorporation of Bi into the catalysts lattice increased the surface area and lowered the overall V oxidation state. Profiles of temperature programmed reduction (TPR) in H2 show a significant shift of the maxima of major reduction peaks to lower temperatures for the Bi-promoted catalysts. A new peak was also observed at the low temperature region for the catalyst with 3% of Bi dopant. The addition of Bi also increased the total amount of oxygen removed from the catalysts. The reduction pattern and reactivity information provide fundamental insight into the catalytic properties of the catalysts. Bi-promoted catalysts were found to be highly active (71% and 81% conversion for 1% and 3% Bi promoted catalysts, respectively, at 703 K), as compared to the unpromoted material (47% conversion). The higher activity of the Bi-promoted catalysts is due to that these catalysts possess highly active and labile lattice oxygen. The better catalytic performance can also be attributed to the larger surface area.  相似文献   

13.
A bismuth(Ⅲ) complex 1 (H2-4,4'-bipy)Bi(HPPA)5(H2PPA)·4H2O (H2PPA = p-hydroxy-phenylacetic acid, 4,4'-bipy = 4,4 -bipyridyl) was hydrothermally synthesized from p-hydroxy-phenylacetic acid (H 2 PPA), Bi(NO 3) 3 ·6H 2 O and 4,4 -bipyridyl, and characterized by elemental analysis, IR, molar conductivity and TG. The single-crystal X-ray diffraction studies demonstrated that the complex is of monoclinic system, space group P21 with a = 10.928(7), b = 22.558(7), c = 11.313(7), β = 91.864(4)°, V = 2787.7(4)3 , Z = 2, C58H61BiN2O22 , Mr = 1347.07, F(000) = 1364, Dc = 1.605 g/cm-3 , μ(MoKα) = 3.247 mm-1 , the final R = 0.0269 and wR = 0.0540 for 9776 observed reflections with Ⅰ > 2σ(Ⅰ). The bismuth(Ⅲ) is seven-coordinated with O atoms, forming a monocapped octahedral geometry. Complex 1 further forms a 3D supramolecular architecture by hydrogen bonds and π-π stacking interactions. Moreover, the interaction between the complex and DNA was studied by EtBr fluoescent probe.  相似文献   

14.
A series of coumarin-chalcone hybrid compounds and coumarins linked to pyrazoline was synthe-sized in good yield and short time using a simple and efficient method. This method involved the one-pot reaction of salicylaldehyde, an α-ketoester and an aromatic aldehyde (in the case of the coumarin-chalcone derivatives) in addition to hydrazine hydrate (in the case of the pyrazolyl cou-marins) in the presence of a catalytic amount of bismuth triflate [Bi(OTf)3, 5 mol%]. The synthesized compounds showed scavenging activity towards the free radical 2,2-diphenyl-1-picrylhydrazyl. All compounds were characterized using IR,1H NMR and13C NMR spectroscopy.  相似文献   

15.
A simple and efficient method has been developed for the one‐pot synthesis of α‐amino phosphonates from the reaction of a carbonyl compound, amine, and dialkyl phosphite. The highly catalytic nature of bismuth(III) chloride and the fact that it is relatively nontoxic, low cost, easy to handle, and insensitive to small amounts of air and moisture make this method especially attractive for large‐scale synthesis.  相似文献   

16.
In this paper, a novel bismuthoxide Schiff-base complex [Bi9O8(vanen)3(NO3)2(CH3OH)2(H2O)·3NO3·5.5H2O](abbreviated as Bivanen) was synthesized with Salen-like ligand H2vanen[H2vanen=N,N'-ethylene bis(3-methoxysalicylideneimine)] and bismuth(Ⅲ) nitrate. Its structure was characterized by IR spectra, NMR spectra and X-ray diffraction. In particular, the biology activities of the ligand and the complex against Schizosaccharomyces pombe(S. pombe) were studied using biological microcalorimetry. The metabolic thermogenic curves of S. pombe were measured at 32.00℃. Then, some quantitative thermokinetic parameters of growth metabolism of S. pombe including the rate constant(k), inhibition ratio(I) and half inhibition concentration(IC50) were calculated. Experimental results showed that the k values of S. pombe decreased while I values of S. pombe increased with the increase of concentrations of the ligand and the complex. The IC50 of the ligand and the complex were found to be 0.067 and 0.037 mmol/L, respectively.  相似文献   

17.
Ultrasound was found to synergistically accelerate the condensation of phenol with β‐ketoesters in the presence of BiCl3. In the absence of ultrasound, under the same conditions, the reaction was found to be slow. Thus, the reaction can be carried out in the presence of ultrasound at room temperature (28–30°C), with a considerable reduction of reaction time, with high yield and high purity of coumarins.  相似文献   

18.
《合成通讯》2013,43(19):3587-3593
Abstract

Tungstophosphoric acid (H3PW12O40 · 6H2O) has been used as a catalyst for a simple, rapid, selective, and solvent‐free cleavage of oximes to carbonyl compounds using iron (III) and bismuth (III) nitrates as oxidants.  相似文献   

19.
Chloride ion batteries(CIB) are considered to be one of the most promising energy storage devices. As cathode materials for CIBs, metal chlorides have many advantages, such as high theoretical energy density, abundant elemental resources and ideal discharge voltage plateau. However, the dissolution and huge volume change of metal chlorides during cycling lead to considerable short lifespan, which limits their potential application for CIBs. Herein, the bismuth chloride nanocrystal is confined in...  相似文献   

20.
Antimony (Sb)-based anodes are attractive candidates in potassium-ion batteries (PIBs) due to their superior capacities and rational potassium inserting voltages. However, the sluggish kinetics and poor interface compatibility severely hinder practical application. Herein, Bi0.67Sb1.33S3 nanospheres embedded into in situ formed poly(3,4-ethylenedioxythiophene) crosslinked with polythioctic acid (PET@PTA) (Bi0.67Sb1.33S3/PET@PTA) were elaborately conceptualized with hydrogen bonds exchangeable binding (HBEB) sites. Bi0.67Sb1.33S3/PET@PTA exhibits notable self-healing ability and wider temperature adaptability. Bi0.67Sb1.33S3/PET@PTA displays an impressive capacity of 819 mAh g−1 at 0.05 A g−1, prominent cycle ability with a 73 % capacity conservation after 500 cycles at 2 A g−1, and high capacity retention of 66 % and 84 % at −40 and 70 °C to that case at room temperature, respectively, for potassium storage. This work provides a new perspective for HBEB sites in maximizing the desirable K+ storage performance.  相似文献   

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