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51.
用热分析(DSC、TG)和FTIR对聚氧化乙烯(PEO)/苯乙烯-马来酸钠(St-alt-MANa,简称SMANa)共聚物共混体系的相容性、分子间作用、热失重等性质进行了研究。结果表明,共混物可以任意比互溶,它们之间的相互作用是PEO的醚键“-O-”和共聚物盐中的“-COOH”之间形成了氢键。TG分析结果表明,随温度的升高,首先形成了酸酐,这可由FTIR光谱确定。热降解产如CO2作为酸酐和共聚物中羧基的降解产物。与不饱和结构相关的谱带(1774cm^-1、1449cm^-1)在350℃和450℃的红外光谱中可观察到,这可能是主要的碳-碳链断裂的结果。共混体系的Tg随SMANa含量的增加而增加,而体系结果温度Tc、熔融温度Tm却略有下降,这说明两组分间具有良好的溶混性。  相似文献   
52.
K3[VO(O2)2(C2O4)]2H2O, (abbr. BpV (ox)) pertains to peroxovanadium (abbr. pV) complexes, which have been attracted considerable attention nowadays, since they are inhibitors of tyrosine phosphatase and may be developed into a new kind of drugs for the treatment of diabetes1. According to the evidence on water-biperoxovanadium, the molecular mechanism of insulin-like effects of pV involves in irreversibly oxidizing the catalytic cysteine at the active site of the target enzyme2,3. However…  相似文献   
53.
Recently, the studies on the interaction of DNA with small molecules have been attracting much interest1-6. These researches not only gave the important information about thermodynamics and kinetics, but also can prompt the combination between the electrode substances and biomacromolecule with super catalysis and sensor character. It is of great significance in understanding energy conversion and metabolism in live body, biomolecular structure, various physical and chemical characters for e…  相似文献   
54.
Calixpyrroles, as new macrocyclic receptors, have gain increasing interest in host-guest chemistry. Pioneering work in this area by Sessler and co-workers have evidenced that calix[4]pyrroles are effective anion binding agents and have used for anion binding, sensing and new anion separation technologies1, 2. In this letter, we report that calix[4]pyrroles A, B and C3,4 (Scheme 1) can serve as additives in CZE for the separa- tion of halide ions. Scheme 1 A B C When analyzing anions with…  相似文献   
55.
Mercaptoalcohols are a rare class of natural products. Some optically active mercaptoalcohols have been used as catalysts in asymmetric reduction of prochiral Ketone1,2. In this letter, we report the synthesis of a new optically active (-mercaptoalcohols, (R)-1,1-diphenyl-2-mercapto-3-methyl-1-butanol 7, from L- valine.Our first attempt is showed in Scheme 1. According to literature's method L-valine was converted to (S)-2-Hydroxy-3-methylbutanoic acid 21,2. 2 was treated with MeOH/SOCl2…  相似文献   
56.
Interactions of DNA with various molecules are interesting because of its importance in gene expression process of living cells. Several models for the interaction between DNA and some small molecules have been proposed1-4. We are interested in the possibility of the interaction between DNA/RNA and neurotransmitters, such as dopamine and epinephrine, because these species are very important substances for keeping normal physiological functions of brain and neuro system. However, no report…  相似文献   
57.
Baker''''s Yeast Mediated Reduction of Optically Active Diketone   总被引:1,自引:0,他引:1  
Baker's yeast (BY) mediated reduction of synthetic substrate is a useful method for preparing chiral intermediate in synthesis chemistry1,2, because it is readily available and inexpensive. The selectivity is generally predicted by Prelog rule3, that is, a hydride is transferred to the re face of the prochiral ketone.The baker's yeast mediated reduction of bicyclic diketones was previously reported by several groups4-6, but to our knowledge, no application of this reduction to sesquiter-pene-…  相似文献   
58.
In recent years, many efforts were focused on the preparation and characterization of phosphazene which contained a framework of alternating phosphorous and nitrogen atoms with two substituent groups attached to each phosphorous atom1. It is noticeable that cyclophosphazene, especially hexaaryloxyphosphazene and perfluoroaryloxyphosphazene exhibit excellent thermal and chemical stability which can be used as fireproof materials, high temperature lubricants, vacuum pump oils and hard disk surfac…  相似文献   
59.
The drug overdose and addiction is a serious international problem. Therefore developing a rapid, accurate, convenient and cheap method for detecting morphine in urea is useful and necessary, especially for investigation of epidemiology, identification of medical jurisprudence and determination of drug addict etc. There are many compounds that are similar to morphine in chemical structure and tend to have cross-reaction with the anti-morphine antibody. In order to reduce the cross reaction a…  相似文献   
60.
Preparing Nano-ZnS by Solid State Reaction at Room Temperature   总被引:3,自引:0,他引:3  
Solid-state reaction has been studied for a long time1-3. In recent years, some researches have been focused on the preparation of coordination compounds at low temperatures or even at room temperature4-5. In this letter, preparation of ZnS nanoparticles by using solid state reaction at room temperature is reported.ZnS nanoparticles were prepared as follows: Zn(CH3COO)2 and Na2S?9H2O, in equal molar ratio, were ground in agate mortar. After 20 minutes, the powder was washed by water and …  相似文献   
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