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91.
A solution of a Zn-complex of recombinant mouse MT-1 isoform (Zn(7)-MT-1) was prepared and titrated with Cd(2+) ions. A method based on the coupling of capillary zone electrophoresis (CZE) with electrospray MS detection was developed for the analysis of the stoichiometry of the species formed during the titration. The method offered the possibility of the on-line removal of up to 100 mM Tris or phosphate buffer solutions that would otherwise suppress the electrospray signal. By allowing the determination of the metal stoichiometry of the complex species present in solution the method was shown to be complementary to circular dichroism and UV-VIS spectrophotometry conventionally used for similar studies. The titration of the Zn(7)-MT complex with Cd(II) showed the sequential displacement of the Zn by Cd. The unusually high stability of the Cd(6)Zn(1)-MT species was observed which suggests a structural role of the remaining Zn(II) ion. 相似文献
92.
Marciniec B Majchrzak M Prukała W Kubicki M Chadyniak D 《The Journal of organic chemistry》2005,70(21):8550-8555
(E)-N-(Silyl)vinylcarbazole has been easily prepared via a new catalytic route, silylative coupling (SC) of vinylcarbazole with vinyltrisubstituted silanes catalyzed by [RuH(Cl)(CO)(PCy3)2]. X-ray structures of two silylvinylcarbazoles as first N-vinylcarbazole derivatives have been resolved. The Pd-catalyzed Hiyama coupling reaction (also as the tandem reaction with SC) of synthesized (E)-N-(triethoxysilyl)vinylcarbazole with iodobenzene has been performed to afford (E)-N-(phenylvinyl)carbazole with high yield and stereoselectivity. 相似文献
93.
Commercially available 1,4-dioxane, even of spectroscopic grade, contains various impurities that arise mostly from reaction of the solvent with oxygen. Aspects relevant to the spectroscopy and photochemistry of the dioxane/oxygen system are discussed. Methods of purification and storage of the solvent are presented. 相似文献
94.
Quasi-isothermal-isobaric analysis was applied as a main method for investigation of thermal decomposition of borates. The
structural mechanism of the dehydration and dehydroxylation of selected borates is considered. It has been found that they
consist of two independent stages: formation of gaseous water molecules localized into the structural framework and their
release. The internal pressure of gaseous water molecules is the factor influencing the course of these processes. The strengths
of the chemical bonds of the components and the freedom of their displacement also determine thermal stability of hydrated
borates.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
95.
Bishop KJ Fiałkowski M Grzybowski BA 《Journal of the American Chemical Society》2005,127(45):15943-15948
Arrays of chemical oscillators are micropatterned by Wet Stamping. The technique is used to demonstrate that chemical waves can be initiated and controlled in oscillatory systems and that such waves can give rise to phenomena not observed in excitable media. Interoscillator coupling and synchronization, kinetic autofocusing, and twist-symmetry breaking are a consequence of the dependence of the oscillation phase on the local concentrations of reagents and on systems' geometry. Conditions under which a generic oscillatory system would exhibit such behaviors are determined. 相似文献
96.
Małgorzata Olejnik Teresa Szprengier-Juszkiewicz Piotr Jedziniak Jan Żmudzki 《Accreditation and quality assurance》2007,12(12):637-641
In this paper, the case of FAPAS PT 0270 “Doramectin and Oxfendazole in Sheep Liver” is discussed. During evaluation of the
data received from participants (determination of total, oxidised oxfendazole residue and calculation of the sum of oxfendazole
and oxfendazole sulfone residues), significant differences were observed between the results obtained by use of two analytical
approaches. This phenomenon can be explained by the route of oxfendazole metabolism, which results in the presence of fenbendazole
in the sample. This was not predicted by the provider; consequently, not all the necessary tests on the material were conducted.
Due to the high uncertainty of the z-scores in this test, the results of the PT cannot be used for purposes of evaluation, and the benefits of participation in
PT 0270 are questionable. 相似文献
97.
P. Staszczuk J. C. Bazan M. Błachnio D. Sternik N. J. Garcia 《Journal of Thermal Analysis and Calorimetry》2006,86(1):57-68
This paper presents possible applications of thermal analysis, sorptometry
and porosimetry to study physico-chemical properties of Na- and La-montmorillonite
samples, especially for determination of total surface heterogeneity. The
quasi-isothermal thermogravimetric (Q-TG) mass loss and its first derivative
(Q-DTG) curves with respect to temperature and time obtained during programmed
liquid thermodesorption under quasi-isothermal conditions have been used to
study adsorbed layers and heterogeneous properties of the Na- and La-montmorillonites.
Calculations of the desorption energy distribution functions by analytical
procedure using mass loss Q-TG and differential mass loss Q-DTG curves of
thermodesorption under quasi-isothermal conditions of polar and non-polar
liquid vapours preadsorbed on a material surface are presented. Parameters
relating to porosity of samples were determined by sorptometry, mercury porosimetry
and atomic force microscopy (AFM). From nitrogen sorption isotherms from sorptometry
and porosimetry methods, the fractal dimensions of montmorillonites have been
calculated. Moreover, a new approach is proposed to calculate fractal dimensions
of materials obtained from Q-TG curve; this is compared with values obtained
by the above methods. The total heterogeneous properties (energy distribution
function and pore-size distribution functions) of samples studied were estimated.
The radius and pore volume of the tested samples calculated on the basis of
thermogravimetry, sorptometry and porosimetry techniques were compared and
good correlations obtained. 相似文献
98.
99.
Kłos J 《The Journal of chemical physics》2005,123(2):24308
Dipole polarizability tensor components and quadrupole moments of transition-metal atoms Sc, Ti, V, Ni, and Cu and ions Sc2+ and Ti2+ are computed using finite field complete active space self-consistent field and multireference configuration interaction ab initio methods. Perpendicular components of the dipole polarizability tensor are calculated from equations involving only parallel components of the polarizability tensor and its average value. Mean polarizability and polarizability anisotropy decrease in the Sc-Ni series. Relativistic effects are accounted for with the Douglas-Kroll Hamiltonian. The consequences of the anisotropic properties of these atoms to their interactions with spherically symmetric rare gases are also discussed. 相似文献
100.
Exchange interactions in copper(II) complexes with tridentate Schiff bases: EPR and magnetic studies
Bogusława Jeżowska-Trzebiatowska Julia Jezierska Jerzy Baranowski 《Chemical physics letters》1977,52(3):590-594
The influence of the nature of ligands upon the magnetic and EPR properties was investigated for the series of polynuclear Cu(II) complexes with tridentate Schiff bases. A similar tendency of changes in the |J| and D parameters was found for binuclear Cu(II) complexes with ligands derived from condensation of 3-amino-1-propanol with 2-hydroxyaldehydes and acetylacetone as well as for Cu(II) complexes with condensation products of o-aminophenol and β-diketones. The Cu(II) complex with Schiff base of 1-amino-2-propanol and acetylacetone exhibits ferromagnetic behaviour suggesting tetrameric structure. 相似文献