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1.
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: |
2.
Heavy metal ions are highly toxic species which can cause long-term damage to biological systems. These species are known
to disrupt biological events at the cellular level, cause significant oxidative damage, and are carcinogens. The production
of simple, in-field detection methods that are highly sensitive for these cations is highly desirable in response to global
pollution. In that regard, bio-inspired colorimetric sensing systems have been developed to detect Hg2+ and Pb2+, and other cations, down to nmol L−1 concentrations. The benefits of these systems, which are reviewed herein, include cost-effective production, facile usage,
and a visual color change for the detection method. Such advantages are significant positive steps for heavy metal ion detection,
especially in regions where sophisticated laboratory studies are prohibited.
Figure Biological-based colorimetric detection of heavy metal cations. The materials on the left are independent Au nanoparticles
in solution, functionalized with heavy metal binding biomolecules, which, upon metal addition, aggregate to evolve a detectable
solution color change.
相似文献
Marc R. KnechtEmail: |
3.
Here, we present a free web-accessible application, developed in the JAVA programming language for the calculation of vicinal
coupling constant (3
J
H,H) of organic molecules with the H–Csp3–Csp3–H fragment. This JAVA applet is oriented to assist chemists in structural and conformational analyses, allowing the user
to calculate the averaged 3
J
H,H values among conformers, according to its Boltzmann populations. Thus, the CAL3JHH program uses the Haasnoot–Leeuw–Altona
equation, and, by reading the molecule geometry from a protein data bank (PDB) file format or from multiple pdb files, automatically
detects all the coupled hydrogens, evaluating the data needed for this equation. Moreover, a “Graphical viewer” menu allows
the display of the results on the 3D molecule structure, as well as the plotting of the Newman projection for the couplings.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
José A. DobadoEmail: |
4.
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.
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O. N. ZefirovaEmail: |
5.
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: |
6.
The crystal and molecular structures of trans-2,4,4-trimethyl-4-silathiane 1-oxide 1 and 4,4-dimethyl-4-silathiane 1,1-dioxide 2 were determined by single crystal X-ray diffraction. Both compounds have the chair conformation with the 2-Me and the S=O
group in compound 1 occupying the equatorial positions. The DFT (B3LYP/6-311G(d,p)) and MP2 (MP2/6-311G(d,p)) theoretical calculations nicely
reproduce the X-ray experimental geometry. The obtained results are discussed in connection with the electronic and structural
properties of the compounds.
相似文献
Bagrat A. ShainyanEmail: |
7.
Malcolm H. Chisholm Jason S. D’Acchioli Christopher M. Hadad 《Journal of Cluster Science》2007,18(1):27-49
The electronic structures and the physical properties (vertical excitation energies, vibrational stretching frequencies, and
bond lengths) of a variety of M–M quadruply bonded (M = Mo, W) complexes are investigated using density functional theory
(DFT). By utilizing a variety of pure and hybrid exchange-correlation (XC) functionals and a number basis sets, we are able
to recommend a theoretical methodology for most efficiently probing the electronic structures of homoleptic M2(O2CR)4 and bridged M2(O2C-X-CO2)M2 (R = organic group, typically H; X = conjugated organic group) complexes.
相似文献
Jason S. D’AcchioliEmail: |
8.
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: |
9.
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: |
10.
Vanézia L. Silva Ruy Carvalho Matheus P. Freitas Cláudio F. Tormena Walclée C. Melo 《Structural chemistry》2007,18(5):605-609
Spectrometric and theoretical tools have been employed in this study in order to elucidate the structures of DTPA (diethylenetriaminepentaacetic
acid) complexed to copper and lead. Mass spectrometry allowed determining the 1:1 stoichiometry of metal:ligand, while infrared
spectroscopy demonstrated that both N and O are sites for complexation. 13C NMR analysis showed the existence of free and complexed carboxyl groups, due to a straight singlet at 180.7 ppm (free carboxylic
13C) and to a broad signal at 179.3 ppm (complexed carboxylic 13C, 2
J
Pb…O=C). A distorted NMR signal were observed for the Cu–DTPA carboxyl group, due to the Cu2+ paramagnetism. Based on the spectrometric evidences for the metal–DTPA structures, DFT optimizations were carried out and
an octahedral-like arrangement for the Cu complex and a “shell-like” arrangement for the Pb complex, both hexa-coordinated,
were then proposed for the structures of the titled compounds.
相似文献
Ruy CarvalhoEmail: |
11.
Catherine Marchal-Roch Estelle Ayrault Laurent Lisnard Jérôme Marrot Feng-Xian Liu Francis Sécheresse 《Journal of Cluster Science》2006,17(2):283-290
The trivacant heteropolyanion A-α[PMo9O31(OH2)3]3− spontaneously dimerizes in acetonitrile to form the Dawson complex [P2Mo18O62]6−. A rapid new quantitative preparation of the sodium salt of this Dawson complex is described. In addition, the structure of TBA5[HP2Mo18O62] is given and the featuring data compared with the isomorphous sodium salt (space group C2/c).
相似文献
Catherine Marchal-RochEmail: |
12.
L. I. Kas’yan I. N. Tarabara Ya. S. Bondarenko L. K. Svyatenko A. V. Bondarenko 《Russian Journal of Organic Chemistry》2007,43(7):1014-1026
Reactions of 4-amino-4-azatricyclo[5.2.1.02,6-endo ]dec-8-ene-3,5-dione (hydrazinolysis product of endic anhydride) with succinic, maleic, cis-cyclohexane-1,2-dicarboxylic, endic, phthalic, and 1,8-naphthalic anhydrides were studied. Procedures for the preparation of the corresponding hydrazido acids and bis-imides were proposed. Their reactions with peroxyformic acid, depending on the substrate nature, led to the formation of both epoxy hydrazido acids and epoxy imides. The unsaturated adducts reacted with p-nitrophenyl azide to give the corresponding triazole derivatives. 相似文献
13.
Stephen L. R. Ellison 《Accreditation and quality assurance》2006,11(3):146-152
The relationship between calibrated range, residual standard deviation and correlation coefficient r is discussed. It is shown that in typical chemical calibration applications with appropriately distributed calibration points (particularly, with range comparable to mean and with approximately even or with ‘successive dilution’ spacing), the linear correlation coefficient has valid application as a routine criterion for acceptable fit if used with due care.
相似文献
Stephen L. R. EllisonEmail: Phone: +44-20-8943-7325Fax: +44-20-8943-2767 |
14.
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: |
15.
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: |
16.
Ilana Abayev Arie Zaban Vladimir G. Kytin Alexey A. Danilin Germà Garcia-Belmonte Juan Bisquert 《Journal of Solid State Electrochemistry》2007,11(5):647-653
Results on the density of sates of nanostructured TiO2 as a function of particle size and temperature are reported. In TiO2 nanoparticles with a mean diameter 10 nm, the density of states (DOS) is strongly temperature-dependent, indicating a rearrangement
of the bandgap states in which the exponential energy parameter (width of the distribution) increases from 0.080 to 50 °C.
For nanoparticles with mean diameters of 20 and 30 nm the DOS is much closer to an exponential distribution, and is much less
sensitive to temperature variations. It is suggested that nanometer confinement has a significant influence on the density
of electronic states for 10-nm particles, while band tailing is similar to that occurring in bulk semiconductors for the larger
particles.
相似文献
Juan BisquertEmail: |
17.
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 |
18.
Necdet Coşkun Aydın Parlar Hasan Karabıyık Muhittin Aygün Orhan Büyükgüngör 《Structural chemistry》2006,17(4):431-438
Carbamoylated oximes 1 form 1:1 molecular complexes 4 with N,N-dialkyl-N′-phenylurea when stirred in THF or ether at room temperature for short time in good yields. The molecular complexes 4a–e were isolated and characterized by analytical and spectral means. X-ray crystallographic analysis for complex 4a was performed. In this paper, we report the use of complex 4a and its moieties as building blocks to form non-interacting polymeric zigzag chains by inter- and intramolecular hydrogen bonds along b-axis, and details of supramolecular architecture of 4a. There is a intramolecular H–H interaction between hydrogen of urea NH and neighboring hydrogen of diisopropyl's CH linked to the other urea nitrogen. In addition, to obtain the most favorable orientation of the moieties of the title complex, PM3 semi-empirical quantum mechanical calculations were performed and then results from X-ray crystallography and computational modeling were compared.
相似文献
Hasan KarabıyıkEmail: |
19.
Attila Sipos Miklós Tóth Franziska K. U. Mueller Jochen Lehmann Sándor Berényi 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):473-478
Abstract The synthesis of 4H-thiochromene derivatives of apomorphines, a novel class of isoquinoline alkaloid-related compounds, has been achieved by
different O-dealkylation methods applied on previously published heteroring-fused aporphinoids. Detailed DFT study has been presented
regarding the mechanism of the L-selectride-mediated multiple O-dealkylation of a seven-ring aporphine analogue. Dopamine-binding tests confirmed the essential function of 11-hydroxy moiety
of the aporphine skeleton and revealed a remarkable D1 over D2 specificity for the derivative having the 4H-thiochromene ring system attached to positions 2 and 3 of the aporphine backbone.
Graphical Abstract
相似文献
Attila SiposEmail: |
20.
Yakov I. Tur’yan Fernando Mata Jorge Moyano Pavel Gorenbein Ron Kohen 《Journal of Solid State Electrochemistry》2007,11(1):10-20
The theory of the polarographic catalytic currents (mechanism CE) has been developed for the system: Ni2+-L-Xp− where L: pyridine (Py), nicotinamide (NA), N,N-diethylnicotinamide (DEN), nicotine (NC) and Xp−: NO−
3, AcO−, HPO2−
4 . The theory is based on the kinetic parallel heterogeneous catalytic reactions:
with the use of Langmuir’s adsorbed isotherm. The kinetic equations obtained for average and instantaneous currents allowed
to determine the Langmuir’s parameters (NA<DEN<NC), kinetic parameters and the contribution of reactions 1a and b to the summary catalytic currents. The k
h″ value rises with the increase of the NiX2−p stability constant. The correlation k
h″≫k
h′ was explained by the additional effect of the field electrode through Xp−. These effects base the reaction 1b instead of accepted early alternative reaction of the ligand exchange. In spite of the fact that k
h″≫k
h′, the contribution of the reaction 1a in the summary catalytic current attained more than 60% (Py, DEN) due to the influence of the ψ0 potential.
Dedicated to Professor Zbigniew Galus on the occasion of his 70th birthday and in recognition of his many contributions to
electrochemistry 相似文献
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