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81.
Cycloaddition of carbon dioxdie and propylene oxide to propylene carbonate catalyzed by tetra-tert-butyl metal phthalocyanine in the presence of tributylamine(TBA) shows higher yield than catalyzed by unsubstituted metal phthalocyanine.Comparing different catalysts of diverse metals,(t-Bu)4PcMg is more active than (t-Bu)PcFe ,But(t-Bu)4PcCo and (t-Bu)4PcNi only have low catalytic activities towards the reaction.Moreover,the yield will increase as the temperature increases. 相似文献
82.
Raman Spectroscopic Investigations of Coordination Polymeric Metal Tricyanmethanides The Raman spectra of 3d-metal tricyanmethanides M{C(CN)3}2 as well as of [Ni{C(CN)3}2py2] are investigated. The observed Raman lines are assigned, characteristic variations of position and intensity of these lines are discussed. 相似文献
83.
由于乙醇最有可能成为直接甲醇燃料电池(DMFC)的替代燃料,因此近年来。对乙醇的电化学氧化及直接乙醇燃料电池的研究已引起人们的很大兴趣。甲醇毒性较大并且易透过Nafion膜进入阴极造成阴极的混合电位而影响DMFC的阴极性能.这是制约DMFC走向实用化的主要问题之一。因此人们在致力于研究直接甲醇燃料电池的同时.也寻求其它的小分子醇作为甲醇的替代燃料。乙醇是除甲醇以外最简单的醇.它来源广泛.无毒,是可再生和环保型能源.并且也有较高的能量密度和反应活性。但是乙醇在电极上的完全氧化因涉及到C-C键的断裂要比甲醇困难.阳极反应动力学过程也比较缓慢。到目前为止铂基催化剂仍然是乙醇氧化最好的催化剂.虽然也有使用非铂催化剂研究乙醇的电氧化,但催化活性远不如铂基催化剂高。 相似文献
84.
85.
Abstract— Irradiation of thin films consisting of 4,5',8-trimethylpsoralen (TMP), adenosine and small amounts of alcohols led to TMP-alcohol photoadducts in addition to TMP-adenosine photoadducts. Four TMP-ethanol and two TMP-methanol adducts have been separated and characterized. Covalent bonds were formed between the 4-carbon of TMP and the α-carbon to the hydroxy group in the alcohols. The TMP-alcohol photoadducts were formed only in the TMP film containing small amounts of alcohol and adenosine. Furthermore, no photoadduct of TMP and ribose was detected upon photolysis of a TMP-ribose film, suggesting that the adenine moiety plays a specific role in the reaction. The interaction of adenosine with psoralens in a dry film may be related to the DNA sequence selectivity observed for the photoreaction of psoralens with DNA. 相似文献
86.
在肽库中进行小肽筛选的初步研究 总被引:1,自引:0,他引:1
以合成六肽DGGSAA为模型对在噬菌体肽库中进行小肽筛选做了初步研究。结果表明,含有可形成氢键和离子键残基的小肽能够在噬菌体肽库中进行筛选。并用明显提高了筛选的专一性。 相似文献
87.
Chang CH Liao JD Chen JJ Ju MS Lin CC 《Langmuir : the ACS journal of surfaces and colloids》2004,20(26):11656-11663
Alkanethiolate self-assembled monolayers (SAMs) of varied chain lengths were adsorbed upon Au-coated nerve microelectrodes and employed as protein-resistant spacers. The microelectrode spiraled as a cuff type can be used for restoring motor function via electrical stimulation on the peripheral nerve system; however, an increase of electrode impedance might occur during implantation. In this work, a thin-film SAMs treatment upon Au/polyimide (PI) surface of the microelectrode provided a hydrophobic characteristic, which retarded protein adsorption at the initial stage and subsequent pileup (or thickening) process. The protein-resistant effect exhibited comparable SAMs of different chain lengths adsorbed upon Au/PI surfaces. The increase of electrode impedance as a function of protein deposition time was mainly correlated with the addition of reactance that was associated with the pileup thickness of the deposited protein. Particularly, the SAMs-modified surface was capable to detach a significant portion of the accumulated protein from the protein-deposited SAMs/Au/PI, whereas the protein-deposited layers exhibited firm adhesion upon Au/PI surface. It is therefore very promising to apply thin-film SAMs adsorbed upon Au-coated surface for bioinvasive devices that have the need of functional electrical stimulations or sensing nerve signals during chronic implantation. 相似文献
88.
Ju Tao LIU Xiao Hong WANG Jing Fu LIU Faculty of Chemistry Northeast Normal University Changchun 《中国化学快报》2004,15(7):859-862
A novel vanadate decamer, involving all vanadium atoms present in +5 oxidation and one formhydroxamic acid dimer cation readical, has been synthesized. The single-crystal X-ray diffraction shows that the orange crystal is formed in the triclinic system, space group Pi, a = 8. 4960 (17), b = 10.447 (2), c = 11.299 (2) A, α= 68. 82 (3)°,β= 87.35 (3)°, γ = 66.97(3)°. V = 855. 3(3) A3, Z = 8, R1 = 0. 0857, wR2=0. 2551. X-ray crystallographic and packing in superlattice studies showed that the crystal structure was constructed by electrostatic attraction of O-H…O hydrogen bonds between formhydroxamic acid dimer cation and decavanadate polyanion. Formhydroxamic acid dimer is got through controlling the condition of the reaction using formhydroxamic acid. 相似文献
89.
烟酸对酸性硫酸盐体系铜电沉积的影响 总被引:2,自引:0,他引:2
对溶液A: 0.8 mol•L-1硫酸铜,0.6 mol•L-1硫酸,5.0×10-5 mol•L-1氯离子,1.0×10-4 mol•L-1聚乙二醇的溶液,溶液B:在溶液A中加入2.0×10-2 mol•L-1烟酸,pH为0.5,运用循环伏安和计时安培法研究玻碳电极上铜的电沉积行为.结果表明,铜的电沉积过程经历了晶核形成过程,其电结晶按瞬时成核和三维生长方式进行.烟酸的加入对铜的电沉积具有阻化作用,但不改变铜的电结晶机理.沉积层的X射线衍射表明Cu为面心立方结构,在烟酸存在下沉积层出现(220)高择优取向,这可能是烟酸在Cu(220)晶面上发生强烈吸附作用的结果. 相似文献
90.
Qing Qing Meng He Xiang Bai Feng Li Quan Rui Wang Feng Gang Tao 《中国化学快报》2007,18(7):785-787
A convenient synthetic pathway to 2-aryl-5,6-dihydro-4H-benzo[f][1,2,4]triazolo[1,5-α]azepine derivatives 7 was developed. The synthesis was based on the cycloaddition of the 1,2,3,4-tetrahydronaphthalene a-acetoxy azo compounds 3 with Ar-CN in the presence of AlCl3 and the consecutive ring enlargement. 相似文献