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The 17-electron species [M(CO)5χLχ] (M Mn, Re, χ 0; M Mn, Re; L Ph3P, χ 1, 2; M Mn, Re; L (o-MeC6H4O)3P, χ 2; M Mn; L (p-ClC6H4O)3P, (PhO)3P, χ 2; M Mn; L P(OMe)3, χ 3) have been generated by one electron oxidation of the corresponding anions and show typical radical reactivity, undergoing dimerisation or hydride abstraction in reactions controlled by steric effects. Evidence is presented for the source of the hydrogen atom. The 19-electron species [M(CO)3(η7-C7H7)]? (M Cr, Mo) and [Fe(CO)3(η5-C6H7)]?, generated by reduction of the corresponding cations, undergo dimerisation at the organic ligand. Similar treatment of [Fe(CO)2-L(η-cp)]+ (L CO, PPh3, P(OPh)3, Me2CO) yields [Fe2(CO)4(η-cp)2] and these reduction reactions are rationalised in terms of the nature of the HOMO in the intermediate radical. Similar reduction of [Rh(diphos)2]+ yield the 17-electron intermediate [Rh(diphos)2] and this also undergoes hydrogen abstraction. 相似文献
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We perform extensive finite difference time domain simulations of ferrite based negative index of refraction composites. A wire grid is employed to provide negative permittivity. The ferrite and wire grid interact to provide both negative and positive index of refraction transmission peaks in the vicinity of the ferrite resonance. Notwithstanding the extreme anisotropy in the index of refraction of the composite, negative refraction is seen at the composite air interface allowing the construction of a focusing concave lens with a magnetically tunable focal length. 相似文献
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Chapatwala Kirit D. Babu G. R. V. Vijaya Onguri K. Armstead E. Palumbo A. V. Zhang C. Phelps T. J. 《Applied biochemistry and biotechnology》1996,57(1):827-835
Applied Biochemistry and Biotechnology - As a part of our study on microbial heterogeneity in subsurface environments, we have examined the microbial respiration of sediment samples obtained from a... 相似文献
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Chromatographic separation of mixed peptides from amino acids in biological digests with volatile buffers. 总被引:3,自引:0,他引:3
Two chromatographic methods, capable of separating mixed peptides from contaminating amino acids in biological digests, are described. Both methods involve separation on copper-Chelex resin, but each uses a different set of elution buffers. When separation method 1 was applied to a commercially available proteolytic digest of casein, the free amino acid content was reduced from 26.0% to 0.5%. With an enzymic digest of 14C-labelled proteins derived from plant biomass, separation method 2 decreased the contaminating free amino acids from 20.3% to 1.9%. Since the separated peptides are eluted with volatile buffers, they are suitable as substrates for biological experiments. 相似文献
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Arunmozhiarasi Armugam Charmian DN Cher KaiYing Lim Dawn CI Koh David W Howells Kandiah Jeyaseelan 《BMC neuroscience》2009,10(1):120
Background
Phospholipase A2 liberates free fatty acids and lysophospholipids upon hydrolysis of phospholipids and these products are often associated with detrimental effects such as inflammation and cerebral ischemia. The neuroprotective effect of neutral phospholipase from snake venom has been investigated. 相似文献6.
We describe a five-step synthesis of 2-(formylmethyl) - cyclopenten-3-one (1a) and its 1-methyl congener (1b) from 6-methylhept-5-ene-2-one by way of the respective 2-(3-methylbut-2-enyl)-cyclopenten-3-ones (5) and selective ozonolysis of these intermediates. 相似文献
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Chapatwala Kirit D. Babu G. R. V. Armstead Eddie R. White Evelyn M. Wolfram James H. 《Applied biochemistry and biotechnology》1995,(1):717-726
Pseudomonas putida capable of utilizing organic nitrile (acetonitrile) and inorganic cyanide (sodium cyanide) as the sole source of carbon and
nitrogen was isolated from contaminated industrial sites and waste water. The bacterium possesses nitrile aminohydrolase (EC
3.5.5.1) and amidase (EC 3.5.1.4), which are involved in the transformation of cyanides and nitriles into ammonia and CO2 through the formation of amide as an intermediate. Both of the enzymes have a high selectivity and affinity toward the−Cn group. The rate of degradation of aceotnitrile and sodium cyanide to ammonia and CO2 by the calcium-alginate immobilized cells ofP. putida was studied. The rate of reaction during the biodegradation of acetonitrile and sodium cyanide, and the substrate- and product-dependent
kinetics of these toxic compounds were studied using free and immobilized cells ofP. putida and modeled using a simple Michaelis-Menten equation. 相似文献
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