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111.
Ester van den Beuken Sylvie Samson Elizabeth J. Sandoe G. Richard Stephenson 《Journal of organometallic chemistry》1997,530(1-2):251-253
The first example of an alkyne-substituted tricarbonyl(η5-cyclohexadienyl)iron(1+) complex has been prepared and the ω directing effect of the phenylethynyl substituent has been demonstrated in nucleophile addition reactions. Addition of NC− also occurs at the a position to form an unusual η1, η3-structure. 相似文献
112.
本文报道由3-氯-1,2-丙二醇(1)经七步反应,合成二羟基丙酮磷酸酯缩乙酮(7)的方法,总收率43%。在温和条件下,7可以水解为游离的二羟基丙酮磷酸酯(8)。 相似文献
113.
Owen S. Jeong B. C. Poole P. S. Macaskie L. E. 《Applied biochemistry and biotechnology》1992,(1):693-707
Tributyl phosphate (TBP), a plasticizer and solvent, is used in nuclear fuel reprocessing, generating TBP wastes laden with
residual uranium. ACitrobacter sp. accumulated heavy metals via a phosphohydrolase(s) that precipitated metals with inorganic phosphate liberated from an
organic phosphate “donor” molecule (TBP). Mutant analysis suggested that TBP hydrolysis was not attributable to a previously
documented acid phosphatase (monoesterase). Purified monoesterase had little activity against phospho di- and triesters, had
no requirement for Mg2+ or Mn2+, and was EDTA-resistant. Conversely, TBP cleavage by immobilized cells was enhanced by Mg2+, and ininhibited by Mn2+ and EDTA. A separate phosphotri/diesterase was implicated. 相似文献
114.
微波溶样肉桂基荧光酮和表面活性剂连续荧光测定葡萄酒中铁和钴 总被引:2,自引:0,他引:2
观察到肉桂基荧光酮(略作CF)在pH≈8与Fc(Ⅲ)配位后荧光增强,CPB的加入使荧光更强,络合物与试剂荧光强度之比F_(FeR)/F_R随0~0.01μg/ml Fe(Ⅲ)线性变化,λ_(ex)=410nm,λ_(ex)=480nm;而CF在pH≈10与Co(Ⅲ)配位后荧光却减弱,乳化剂OP存在时使试剂荧光增强,若以荧光熄灭Co(Ⅲ)灵敏度便提高,试剂与络合物荧光强度之比F_R/F_(CoR)对0~0.016 μg/ml Co(Ⅲ)呈直线关系,λ_(ex)=300nm,L_(em)=352nm。控制化学条件和激发、发射波长,可不经分离测定葡萄酒(微波溶样)中铁和钴。 相似文献
115.
In this paper the formation mechanism of iron macro-spheres in
a plasma medium is dealt with, including the conditions under which such
spheres are formed. The geometry of the spheres referred to above
depends on the main technological parameters involved in the production
of pores. Conditions under which pores occur within macro-spheres are
also established. The radii of these pores are sensitive to the velocity
distribution within the plasma jet section 相似文献
116.
Cerium phosphate nanoparticles with diameters of 10-180 nm were synthesized by a variety of solution techniques. X-ray diffraction (XRD) determined the crystalline phase(s) present in each sample. Population, shift, and spin-lattice relaxation 31P solid-state nuclear magnetic resonance (NMR) measurements accounted for all the 31P nuclei expected in each sample, and were able to distinguish between phosphorous nuclei in different environments and phases. Transmission electron microscopy (TEM) characterized the morphology and crystallinity of the powder samples as well as of the sintered compacts of the powders. In conjunction with TEM, energy-dispersive spectroscopy (EDS) provided a measure of the composition of the bulk intergranular regions within each CePO4 sample. The presence of an amorphous, phosphate-rich intergranular phase was found in those samples prepared by dissolution of ceria in H3PO4 under various conditions. 相似文献
117.
采用高温固相反应合成了磷酸钡钙∶铈、锰红色荧光粉。借助TG,XRD,荧光粉相对亮度仪、荧光分光光度仪等手段系统研究了合成过程中原料化学组成及配比、合成条件对磷酸钡钙∶铈、锰发光性能的影响。结果表明,荧光粉基质(BaxCa1-x)3(PO4)2具有畸变的Ca3(PO4)2结构。该荧光粉中Ce3+是助激活剂,Mn2+是激活剂,由Ce3+→Mn2+的能量传递使Mn2+激发产生650 nm左右的发射,当Ce3+和Mn2+浓度相等且都为0.15时,荧光粉有最高的红色发射亮度。 相似文献
118.
Syntheses, Structure Determination and Reactions of Phosphine Substituted Derivatives of Fe3(CO)9(μ3-CF)2 Photolysis of Fe3(CO)9(μ3-CF)2 1 in the presence of acetonitrile 2a or benzoenitrile 2b results in the substitution of a single carbonyl ligand by a nitrile ligand yielding Fe3(CO)8(CH3CN)(μ3-CF)2 3a and Fe3(CO)8(C6H5CN)(μ3-CF)2 3b, respectively. The acetonitrile ligand in 3a can be easily replaced by trimethyl-phosphine 4a or triphenylphosphine 4b . The monosubstituted compounds Fe3(CO)8(PR3)(μ3-CF)25, R = CH3 a, R = C6H5, b are obtained as major products besides a small amount of the disubsituted products Fe3(CO)7(PR3)2(μ3-CF)2 6. The structure of 5a has been elucidated by a single crystal X-ray structure determination. Thermal ligand substitution in 1, however, results in the formation of a mixture of mono-, disubstituted, and trisubstituted products, in which 6b is the major product for diphenylphosphine. 5a reacts with ethyne 7 forming a phosphine substituted diferra-allyl-cluster Fe3(CO)7(PR3)(μ3-CF)(μ3? CF? CH? CH) 8. The structure of one isomere of 8 has been determinated by X-ray crystallography. 相似文献
119.
根据Fe(Ⅲ)、Mo(Ⅵ)对H2O2氧化邻氨基酚的催化反应速率不同,结合流动注射停留技术,建立了同时测定Fe(Ⅲ)、Mo(Ⅵ)的速差动力学分光光度法.测定铁和钼的线性范围分别为0.1~2.5μg/mL和0.5~15μg/mL.除W(Ⅵ)的允许量较小外,其它离子不干扰测定.用本法测定了合成样液中铁和钼含量,结果满意. 相似文献
120.
Various computational approaches, using molecular mechanics (Amber), semiempirical (AM1), density functional (B3LYP), and various ONIOM methods, have been comparatively investigated for the structure of Escherichia coli NifS CsdB protein. The structure of the entire monomer containing 407 amino acid residues and 579 surrounding water molecules has been optimized. The full geometry optimization in the "active site-only" approach (including only active site atoms) has been found to give the largest root-mean-square (RMS) deviation from the X-ray structure; a much better agreement has been achieved by keeping the atoms leading to the backbones of some amino acids frozen in their positions in the X-ray structure. The best agreement has been attained by including the surrounding protein in the calculations using the two-layer ONIOM (B3LYP:Amber) approach. The results presented in this study conclusively demonstrate the importance of the protein/active-site interaction on the active-site structure of the enzyme. The present theoretical study represents the largest system studied at the ONIOM level to date, containing 7992 atoms, including 84 atoms in the QM region and rest in the MM region. 相似文献