共查询到20条相似文献,搜索用时 27 毫秒
1.
Davorka Moslavac Forjan Marijana Vinković Darko Kontrec Andreja Lesac Vladimir Vinković 《Structural chemistry》2007,18(5):585-591
Doubling of resonances in NMR spectra of chiral selectors with naphthyl group attached to the tertiary amide nitrogen atom
has been noticed what revealed the presence of two isomers. To test the enantiorecognition ability of these chiral selectors
they are covalently bonded to the HPLC silica gel. Those kind of chiral stationary phases were compared with analogous commercial
leucine chiral stationary phase. They exhibit the better enantioseparation results which indicate that the existence of cis/trans isomers does not have the negative influence on their enantioselective ability.
相似文献
Vladimir VinkovićEmail: |
2.
3.
Vaporization enthalpies for the isomeric diazines were discussed within the context of recent measurements and estimation
techniques. It is suggested that pyridazine shows enigmatic behavior.
相似文献
Joel F. Liebman (Corresponding author)Email: |
4.
Guy Yardeni Israel Zilbermann Eric Maimon Haim Cohen Dan Meyerstein 《Research on Chemical Intermediates》2009,35(4):543-554
A new CeIII complex was synthesized by mixing the ligand “dioxocyclam” with CeIII ions at pH 8.0 and its redox properties were investigated.
相似文献
Dan Meyerstein (Corresponding author)Email: |
5.
The kinetic of the sol–gel hydrolysis and polycondensation reactions of a chiral ORMOSIL precursor was investigated by LCMS
technique as a function of water excess and pH. While the amount of water does not significantly change the kinetics, the
reactions strongly depend on the [H]+ concentration. At pH ≤ 3, the hydrolysis is very fast and the conversion of the precursor is completed within less than 1
h whereas at 80% of the precursor is still present after 50 h at pH = 3.5. This kinetic study allows to define a set of initial
conditions and time ranges required to provide good optical quality dip coated films .
相似文献
L. GuyEmail: |
6.
Yan Gao Sabrina Reischmann Johannes Huber Tobias Hanke Rudolf Bratschitsch Alfred Leitenstorfer Stefan Mecking 《Colloid and polymer science》2008,286(11):1329-1334
Single semiconductor quantum dots were embedded into polymer particles with diameters below 0.1 μm by an emulsion polymerization
procedure or via a secondary dispersion approach. The photoluminescence properties of the nanocrystals are retained upon encapsulation,
as demonstrated by fluorescence confocal microscopy.
相似文献
Stefan MeckingEmail: |
7.
Michael Thompson 《Accreditation and quality assurance》2008,13(8):479-482
The currently recommended design of collaborative trials (interlaboratory method performance studies) is examined in relation
to the usefulness of the resulting statistics. It is suggested that larger experiments, without duplicate analysis, would
be more informative.
相似文献
Michael ThompsonEmail: |
8.
Hinne Hettema 《Foundations of Chemistry》2008,10(2):135-142
Michael Weisberg’s recent 2007 paper on the chemical bond makes the claim that the chemical notion of the covalent bond is
in trouble. This note casts doubts on that claim.
相似文献
Hinne HettemaEmail: |
9.
Niki Baccile Anna Fischer Beatriz Julián-López David Grosso Clément Sanchez 《Journal of Sol-Gel Science and Technology》2008,47(2):119-123
Core-shell and homogeneous distributions of functionalized cerium oxide nanoparticles within spray-dried mesostructured silica
spheres are achieved by modification of synthesis parameters such as the templating agent and nanoparticle capping functions.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Clément Sanchez (Corresponding author)Email: |
10.
Electrochemical copolymerization of furan and 3-chlorothiophene was performed at constant electrode potential in a binary
solvent system consisting of boron trifluoride diethyl etherate + ethyl ether (BFEE + EE; ratio 1:2) and trifluoroacetic acid
(10% by volume). The homopolymers and copolymers obtained were studied with cyclic voltammetry, in situ ultraviolet–visible
spectroscopy, in situ resonance Raman spectroscopy, and in situ conductivity measurements. The spectroelectrochemical properties
of the copolymers show intermediate features between polyfuran and poly(3-chlorothiophene). The conductivity changes of homo-
and copolymer films are almost completely reversible when the potential shift direction is reversed.
相似文献
Rudolf HolzeEmail: |
11.
Saad Alshehri John Burgess Colin D. Hubbard Christopher J. Jones Amit K. Das 《Transition Metal Chemistry》2008,33(4):417-420
The kinetics of substitution by alcohols and by aniline at [tris(3,5-dimethylpyrazolyl)hydroborato]molybdenum nitrosyl dihalides in toluene solution at 298.2 K and at atmospheric pressure
are reported and interpreted in terms of an associative mechanism.
相似文献
Colin D. HubbardEmail: |
12.
O. N. Zefirova L. A. Zasurskaya E. V. Nurieva N. V. Zyk N. S. Zefirov 《Structural chemistry》2007,18(4):461-464
Molecular structure of ethylene acetal of 3-trityloxymethylbicyclo[3.3.1]nonane-2-on-7-ol (3) was determined by X-ray investigation. It was revealed that 3 has endo-endo-configuration and adopt chair-boat-conformation. The distortion of rings was evaluated by calculation of the Zefirov–Palyulin and Cremer–Pople puckering parameters.
Failure of esterification of 3 was rationalized in terms of steric hindrance and intramolecular hydrogen bonding.
相似文献
O. N. ZefirovaEmail: |
13.
H. P. Zhang L. C. Yang L. J. Fu Q. Cao D. L. Sun Y. P. Wu R. Holze 《Journal of Solid State Electrochemistry》2009,13(10):1521-1527
Recent progress in studies of several types of core-shell structured electrode materials, including TiO2/C, Si/C, Si/SiO
x
, LiCoO2/C, and LiFePO4/C nanocomposites, including details of their preparation and their electrochemical performance is briefly reviewed. Results
clearly show that the coating shell can effectively prevent the aggregation of the nanosized cores, which are the electrochemically
active materials. In addition, the diffusion coefficients of lithium ions can be increased, and the reversibility of lithium
intercalation and deintercalation is improved. As a result, the cycling behavior is greatly improved. The reviewed results
suggest that core-shell nanocomposites are a good starting point for further development of new promising electrode materials.
相似文献
Y. P. WuEmail: |
R. Holze (Corresponding author)Email: |
14.
Superhydrophobic surfaces were obtained by coating with microspheres formed by the self-assembly of poly[2-(perfluorooctyl)ethyl
acrylate-ran-2-(dimethylamino)ethyl acrylate] (P[POA-r-DAA]) in the presence of dicarboxylic acids in supercritical carbon dioxide. The P[POA-r-DAA] random copolymer aggregated into micellar microspheres through the hydrogen bond cross-linking of the amino groups via
the carboxylic acids. The size of the microspheres and the amount of the acids needed to produce them were dependent on the
kinds of acids. Glutaric acid (Glu) and perfluorosuccinic acid (Psuc) provided microspheres at a 0.5 molar ratio of the acid/DAA.
Psuc produced smaller microspheres than Glu. Maleic acid (Ma), succinic acid (Suc), and azelaic acid (Az) required a higher
molar ratio to produce the microspheres. These acids provided spherical particles at the ratio of 1.0. The microspheres produced
by Suc and Az contained particles with a several hundred nanometer size. The surface coated with the microspheres showed high
water contact angles of 164°–172°.
相似文献
Eri YoshidaEmail: |
15.
René Dybkaer 《Accreditation and quality assurance》2007,12(12):661-663
Terminology within a small laboratory community can be informal without danger of misunderstanding, but communication with
a wider audience and not least in publications, needs unequivocal terms for defined concepts. As an example, the many meanings
of “concentration” are explored to present a systematic nomenclature, including a concept diagram.
相似文献
René Dybkaer |
16.
Electrochemical studies of bi- and polymetallic complexes featuring acetylide based bridging ligands
Paul J. Low Rachel L. Roberts Richard L. Cordiner František Hartl 《Journal of Solid State Electrochemistry》2005,9(11):717-731
Acetylide-based bridging ligands have been widely used in the preparation of complexes that display a degree of electronic
interaction between metal-based redox groups located at the ligand termini. The electrochemical response of these systems
has been selectively reviewed, with a focus on the variation in properties that accompany changes in the structure of the
bridging ligand and the nature of the metal groups.
相似文献
Paul J. LowEmail: |
17.
The molecular geometries, relative stabilities, binding energies, and dissociation energies of NaDyBr4 and its molecular ion are discussed. Both the bidentate and tridentate isomers are stable for the neutral species, while
only the bidentate form is stable for NaDyBr4
+.
相似文献
Magdolna Hargittai (Corresponding author)Email: |
18.
Michael Noyong Buelent Ceyhan Christof M. Niemeyer Ulrich Simon 《Colloid and polymer science》2006,284(11):1265-1273
The formation and the optical features of two-dimensional aggregates formed by DNA-directed immobilization and cross-linking of bifunctional DNA–gold nanoparticles at flat gold substrates are analyzed. The samples are structurally characterized by atomic force microscopy to evaluate the particle size, the particle densities, and the degree of aggregation. The optical characteristics determined by UV/visible measurements are correlated with the structural features observed.
相似文献
Ulrich SimonEmail: |
19.
The estimation of electrochemical quartz crystal microbalance (EQCM) frequencies from a given cyclic voltammetric data is analysed using underpotential deposition (UPD) of metals as an illustrative process. The crucial role played by the surface roughness of electrodes and electrosorption valency of the depositing species is pointed out. The computed EQCM frequency shifts for the UPD of Cd and Tl on polycrystalline Ag electrodes are in satisfactory agreement with the experimental data.
相似文献
M. V. SangaranarayananEmail: |
20.
Hitoshi Shirase Yurie Miura Yutaka Fukuda 《Monatshefte für Chemie / Chemical Monthly》2009,140(7):807-814
Abstract Mixed-ligand NiII complexes have been synthesized with 1,3-diketonate and bulky tri- or tetra-amine ligands. Their structures were determined
by X-ray crystallography, and solvatochromic behavior was examined by UV–vis–NIR spectroscopy. Steric effects of the bulky
ligands on the coordination distances and spectral properties are discussed.
Graphical Abstract
相似文献
Yutaka FukudaEmail: |