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971.
Vega A Calvo V Spodine E Zárate A Fuenzalida V Saillard JY 《Inorganic chemistry》2002,41(13):3389-3395
The reaction of the organometallic carboxylic acid HOOCCCHCo(2)(CO)(6) with copper(II) methoxide leads to a new inorganometallic cluster; Cu(3)[mu(2)-(CCHCo(2)(CO)(6))](3). This cluster has a triangular core of copper(I) centers surrounded by three CCHCo(2)(CO)(6) fragments. The structure of the cluster has short Cu-Cu and Cu-Co distances (average 2.500 and 2.540 A, respectively). DFT calculations provide a rationalization of the peculiar bonding in this cluster. 相似文献
972.
The solubility of siderite (FeCO3) at 25°C under constant CO2 partial pressure [p(CO2)] was determined in NaCl solutions as a function of ionic strength. The dissolution of FeCO3(s) for the reaction
has been determined as a function of pH = – log[H+]. From these values we have determined the equilibrium constant for the stoichiometric solubility to FeCO3(s) in NaCl
These values have been fitted to the equation
with a standard error of s = 0.15. The extrapolated value of log(K
o
sp) – 10.9 in water is in good agreement with data in the literature (– 10.8 to – 11.2) determined in solutions of different composition and ionic strength.The measured values of the activity coefficient, T(Fe2+) T(CO3
2–), have been used to estimate the stability constant for the formation of the FeCO3 ion pair, K*(FeCO3). The values of K*(FeCO3) have been fitted to the equation (s = 0.09)
The value of log[K
o(FeCO3)] in water found in this study (6.3 ± 0.2) is slightly higher than the value found from extrapolations in 1.0 m NaClO4 solutions (5.9 ± 0.2). These differences are related to the model used to determine the activity coefficients of the Fe(II) and carbonate species in the two solutions. 相似文献
973.
Villa de P AL Alarcón E Montes de Correa C 《Chemical communications (Cambridge, England)》2002,(22):2654-2655
MCM-41 was found to be an active heterogeneous catalyst for the synthesis of nopol by the Prins condensation of beta-pinene and paraformaldehyde, but Sn-MCM-41 in which Sn has been grafted on MCM-41 by chemical vapor deposition is far more active and combines high efficiency and recyclability. 相似文献
974.
Novel intramolecular TaqMan probes have been evaluated on the W1282X locus of the human ABCC7 gene and shown to be more efficient than traditional TaqMan probes. 相似文献
975.
Morilla ME Morfes G Nicasio MC Belderrain TR Mar Díaz-Requejo M Graiff C Tiripicchio A Sánchez-Delgado R Pérez PJ 《Chemical communications (Cambridge, England)》2002,(17):1848-1849
N,N, N',N'-Tetraethylethylenediamine undergoes simple or double intramolecular dealkylation reactions in the presence of the complexes [RuCl2(diene)]n (diene = cod, nbd) or trans-[RuCl2(diene)(morfoline)2 at 80 degrees C to afford chelating amine ligands which contains one or two N-H functionalities. 相似文献
976.
Cyclic carbonate formation from carbon dioxide and oxiranes in tetrabutylammonium halides as solvents and catalysts 总被引:1,自引:0,他引:1
[reaction: see text] Epoxides dissolved in molten tetralkylammonium salts bearing halides as counterions are converted into cyclic carbonates under atmospheric pressure of carbon dioxide. The reaction rate depends on the nucleophilicity of the halide ion as well as the structure of the cation. 相似文献
977.
An impedance study of the adsorption of nucleic acid bases at glassy carbon electrodes 总被引:5,自引:0,他引:5
Oliveira-Brett AM Brett CM Silva LA 《Bioelectrochemistry (Amsterdam, Netherlands)》2002,55(1-2):33-35
Polyamidoamine (PAMAM) dendrimers (generation 3.5 and 4) interaction with bovine serum albumin (BSA) was studied. The intensity of intrinsic fluorescence of two tryptophan residues and a shift in wavelength of their emission maxima were chosen as indicators of protein conformational changes. It is shown that the generation 4 has a greater impact on spectral properties of serum albumin than generation 3.5. 相似文献
978.
The role of hydrogenases in the anaerobic microbiologically influenced corrosion of steels 总被引:1,自引:0,他引:1
The direct electron transfer between 316 L stainless steel and the NAD-dependent hydrogenase from Ralstonia eutropha was studied by spectroelectrochemistry. The presence of hydrogenase and NAD+ clearly increased the quantity of electricity, which was consumed during the electrolysis performed at potential lower than -0.70 V/SCE. The involvement of hydrogenase in the cathodic depolarisation theory was discussed in the light of these results. 相似文献
979.
An electrochemical DNA-biosensor has been used to investigate the interactions between DNA and members of a group of ten derivatives of 1,3,5-triazine herbicides: chloro-s-triazines (atrazine, propazine, terbutylazin, and cyanazin), thiomethyl-s-triazines (ametryn, prometryn, terbutryn, and simetryn), and methoxy-s-triazines (prometon and terbumeton). A UV spectrophotometric study of this group of herbicides was also undertaken. Of this group only cyanazin could be oxidized in aqueous solution using a glassy carbon electrode. Use of the electrochemical DNA-biosensor revealed the occurrence of a time-dependent interaction of all the herbicides with DNA, via the appearance of guanine, guanosine, and adenosine oxidation signals that correspond to DNA damage. Adduct formation between the herbicide and the DNA purine bases guanine and adenine is suggested as a mechanism. 相似文献
980.
We show theoretically that the waves generated through the generic parametric three- or four-wave-mixing processes exhibit, as a general rule, a hidden coherence characterized by skewed coherence lines along specific space-time trajectories. Our study generalizes the concept of coherence in the sense that these previously unrecognized coherent states cannot be described through the standard definitions of spatial and temporal coherence. 相似文献