排序方式: 共有135条查询结果,搜索用时 15 毫秒
51.
Serpil Demir Yasemin Gökçe Nazan Kaloğlu Jean‐Baptiste Sortais Christophe Darcel İsmail Özdemir 《应用有机金属化学》2013,27(8):459-464
A series of new piano‐stool iron(II) complexes comprising N‐heterocyclic carbene ligands [Fe(Cp)(CO)2(NHC)]I (NHC = 1,3‐disubstituted imidazolidin‐2‐ylidene) have been synthesized and analyzed by 1H NMR, 13C NMR, IR, elemental analysis and mass spectrometric techniques. These compounds were easily prepared from the reaction of disubstituted imidazolidin‐2‐ylidene with [FeI(Cp)(CO)2] in toluene at room temperature. These complexes were tested in the catalytic hydrosilylation reaction of aldehydes and ketones with phenylsilane in solvent‐free conditions. After a basic hydrolysis step, the corresponding alcohols were obtained in good yields. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
52.
Rafet Kılınçarslan M. Emin Günay Rukiye Fırıncı Serpil Denizaltı Bekir Çetinkaya 《应用有机金属化学》2016,30(5):268-272
A new series of sterically hindered ligands containing (1R,2S,4R)‐(+)‐menthoxymethyl group attached to benzimidazole‐based N‐heterocyclic carbene (NHC), palladium–bis‐NHC complexes and (κ2‐C,N)‐palladacyclic NHC complexes have been synthesized and characterized using appropriate spectroscopic techniques. Catalytic performance of the palladium complexes has been investigated for allylic alkylation, Suzuki and Heck carbon–carbon coupling reactions. These complexes smoothly catalyse the carbon–carbon bond formation reactions. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
53.
54.
Cemil İbiş F. Serpil Göksel Gökşin Aydınlı 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):777-783
Reaction of 2-nitropentachlorobutadiene with thiols and amines gave new N,S- and S,S-substituted nitrodiene compounds is discussed. 相似文献
55.
Huseyin Bekir Yildiz Dilek Odaci Demirkol Serkan Sayin Mustafa Yilmaz Ozcan Koysuren Musa Kamaci 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1075-1084
Accumulation of cholesterol in human blood can cause several health problems such as heart disease, coronary artery disease, arteriosclerosis, hypertension, cerebral thrombosis, etc. Therefore, simple and fast cholesterol determination in blood is clinically important. In this study, two types of amperometric cholesterol biosensors were designed by physically entrapping cholesterol oxidase in conducting polymers; thiophene capped poly(ethyleneoxide)/polypyrrole (PEO-co-PPy) and 3-methylthienyl methacrylate-co-p-vinyl benzyloxy poly(ethyleneoxide)/polypyrrole (CP-co-PPy). PEO-co-PPy and CP-co-PPy were synthesized electrochemically and cholesterol oxidase was immobilized by entrapment during electropolymerization. The amperometric responses of the enzyme electrodes were measured by monitoring oxidation current of H2O2 at +0.7 V in the absence of a mediator. Kinetic parameters, such as Km and Imax, operational and storage stabilities, effects of pH and temperature were determined for both entrapment supports. Km values were found as 1.47 and 5.16 mM for PEO-co-PPy and CP-co-PPy enzyme electrodes, respectively. By using these Km values, it can be observed that ChOx immobilized in PEO-co-PPy shows higher affinity towards the substrate. 相似文献
56.
Serpil Aközcan Mücahit Yılmaz Fatih Külahcı 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):95-101
Concentrations of 238U, 232Th, 226Ra, 40K and 137Cs are measured in collected soil samples from various locations in the Thrace region of Turkey. The activity concentrations range from 12.82 to 101.75 Bq kg?1 d.w. (dry weight) for 238U, from 5.16 to 73.34 Bq kg?1 d.w. for 232Th, from 185.54 to 5399 Bq kg?1 d.w. for 40K and from 11.42 to 90.73 Bq kg?1 d.w. for 226Ra. In addition to naturally occurring radionuclides, 137Cs activity concentration is determined between 3.05 and 46.78 Bq kg?1 d.w. for soil samples. Determination of the radiological hazard is achieved through calculations of the external terrestrial gamma dose rate in air (nGy h?1) and annual effective dose rate (mSv year?1) and the results are compared with the similar works in different countries. 相似文献
57.
A highly effective, easy to handle and environmentally benign process for palladium‐mediated Suzuki cross‐coupling is developed. The in situ prepared three‐component system Pd(OAc)2–1,3‐bis(alkyl)imidazolinium chlorides (2a–f) and Cs2CO3 catalyses quantitatively the Suzuki cross‐coupling of deactivated aryl chlorides. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
58.
A parametric study to increase the enantioselectivity of Candida rugosa lipase (CRL) toward S-Naproxen production by the hydrolysis of racemic Naproxen methyl ester in an aqueous-organic biphasic
batch system was carried out. Effects of organic solvent type, aqueous phase/organic solvent volume ratio, agitation rate,
concentrations of the substrate and the enzyme, pH of the aqueous phase, and temperature on the en antiomeric excess for the
product (eep), on the enantiomeric ratio (E) and on the conversion (x) were evaluated. Employing isooctane as the solvent resulted in
higher eep, E, and x than those obtained in hexane, cyclohexane, and toluene. The higher the volume ratio of aqueous phase/organic solvent
employed, the higher the conversion and enantioselectivity achieved. The increase in agitation rate increased the hydrolysis
rate. Higher concentration of racemic Naproxen methyl ester than 10 mg/mL decreased both the conversion and enantioselectivity.
The increase in crude CRL concentration resulted in enhancement of x, but the decrease of feep and E. Acidic pH led to higher conversion and enantioselectivity than the medium and alkaline pH values. A further increase
in temperature to over 45°C decreased the conversion and enantioselectivity. The highest enantiomeric ratio achieved in the
S-Naproxen production was E=171.1, with x=49.8% and eep=95.7%. 相似文献
59.
The reaction of the boron hydride B4H10 with allene was studied at the CCSD(T)/6-311+G(d)//MP2/6-31G(d) level. The mechanism is surprisingly complex with 44 transition states and several branching points located. The four carboranes and one basket that have been observed experimentally are all connected by pathways that have very similar free energies of activation. In addition, two new structures, a basket (2,4-(CH2CH2CH2)B4H8, 5a) and a "classical" structure (1,4-(Me2C)bisdiborane, 7), which might be obtained from the B4H10 + C3H4 reaction under the right conditions (hot/cold, quenched, etc.) have been identified. The first branch point in the reaction is the competition between H2 elimination from B4H10 (DeltaG(298 K) = 32.2 kcal/mol) and the hydroboration of allene by B4H10 (DeltaG(298 K) = 31.3 kcal/mol). The next branch point in the hydroboration mechanism controls the formation of 2,4-(MeCHCH2)B4H8 (1) (DeltaG(298 K) = 31.5 kcal/mol) and arachno-1,2/arachno-1,3-Me2-1-CB4H7 (8 and 8a) (DeltaG(298 K) = 34.3 kcal/mol). Another branch point in the H2-elimination mechanism controls the formation of 1-Me-2,5-micro-CH2-1-CB4H7 (29) (DeltaG(298 K) = 0.1 kcal/mol) and 2,5-micro-CHMe-1-CB4H7 (25/26) (DeltaG(298 K) = 7.3 kcal/mol). Formation of 2-Me-2,3-C2B4H7, a carborane observed in the reaction of methylacetylene with B4H10, is calculated to be blocked by a high barrier for H2 elimination. All free energies are relative to B4H10 + allene. An interesting reaction step discovered is the "reverse hydroboration step" in which a hydrogen atom is transferred from carbon back to boron, which allows a CH hydrogen to shuttle between the terminal and central carbon of allene. 相似文献
60.
Friedländer synthesis of 2-acylquinolines from the reaction of symmetrical and unsymmetrical 1,2-diketones with 2-aminoarylketones in the presence of indium triflate (In(OTf)3) and ionic liquid gives quantitative yields. Once the reaction was completed, the catalysts can be recovered and subsequently run for next cycles. Results obtained from theoretical studies have been more strengthened by FT-IR, FT-NMR chemical shifts, and structural parameters which were attained with B3LYP/6-31G(d,p) level of theory and the related results were demonstrated with the experimental interpretations. 相似文献