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21.
Baber RA Charmant JP Cook AJ Farthing NE Haddow MF Norman NC Orpen AG Russell CA Slattery JM 《Dalton transactions (Cambridge, England : 2003)》2005,(19):3137-3139
Treatment of the diborane(4) compound B(2)(NMe(2))(4) with aniline or 2,6-dimethylaniline results in the primary amido compounds B(2)(NHR)(4)(R = Ph, 2,6-Me(2)C(6)H(3)); subsequent treatment with n-BuLi in toluene in each case affords the first examples of anionic imidodiborates namely Li(4)(thf)(6)B(2)(NPh)(4) and Li(4)(thf)(4)B(2)(N-2,6-Me(2)C(6)H(3))(4); all complexes have been characterised crystallographically. 相似文献
22.
In order to find support for the validity of the hypothesis proposed by one of us regarding the different natures of the bonds in the four successive complexes formed between Ag+ and thiourea, the corresponding enthalpies are verified by direct calorimetry.Furthermore, because the influence of substituent groups on the nitrogen atoms may help to characterize the donor atom. the calorimetric enthalpies and potentiometric free energies of complexation between Ag+ and N-methylthiourea, N,N′- dimethylthiourea and N,N′-diethylthiourea have also been determined at 25°C, in aqueous medium of ionic strength μ = 0.5 M KNO3. 相似文献
23.
Cosper MM Jameson GN Davydov R Eidsness MK Hoffman BM Huynh BH Johnson MK 《Journal of the American Chemical Society》2002,124(47):14006-14007
The combination of resonance Raman, electron paramagnetic resonance and M?ssbauer spectroscopies has been used to investigate the effect of S-adenosyl-l-methionine (SAM) on the spectroscopic properties of the [4Fe-4S]2+ cluster in biotin synthase. The results indicate that SAM interacts directly at a unique iron site of the [4Fe-4S]2+ cluster in BioB and support the hypothesis of a common inner-sphere mechanism for the reductive cleavage of SAM in the radical SAM family of Fe-S enzymes. 相似文献
24.
Guy Guelachvili K. Narahari Rao Richard H. Tipping Brenda P. Winnewisser Manfred Winnewisser 《Mikrochimica acta》1988,95(1-6):339-343
This paper reports the observation of the far infrared absorption spectrum of a single crystal of N2, measured over absorption paths of 4 cm (lengthwise) and 2 cm (across the crystal). The crystal chamber, with quartz windows, was immersed in a flow of cold helium gas. The spectrum from 20 to 120 cm–1 was recorded in the liquid phase, the-phase, and over the full temperature range of the-phase (35.6–2.0 K) with a Fourier transform spectrometer. The spectral resolution, which was not instrument-limited, and the large path allowed the observation of more detailed multiphonon-transition structure in the spectrum of the-phase than has previously been observed. 相似文献
25.
A series of 2-substituted 4H-3,1-benzoxazinones and 2,3-disubstituted 4-(3H)quinazolinones have been synthesized in mild conditions by the use of triphenyl phosphite and pyridine as cyclising medium. Benzox-azinones are produced either by ring closure of 2-(acylamino)benzoic acids or in the reaction of benzoic acid with anthranilic acids. In the presence of aniline, the reaction leads to quinazolinones. 相似文献
26.
Infant formula powders were analyzed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) to assess the whey proteins quality, which may be altered by the heat treatment used during the processing conditions. Lactosylation was found to be the major chemical modification occurring in whey proteins. In parallel, a two-dimensional (2-D) gel electrophoresis was performed on the milk sample and the entire protein patterns were analyzed by nano-ESI-MS after cutting the different gel spots and in-gel trypsin digestion. A highly selective and specific tandem MS technique has been developed to characterize and localize up to ten lactosylation sites in beta-lactoglobulin (beta-Lg) and alpha(S2)-casein. alpha-Lactalbumin (alpha-La), with five lactosylated peptides, was found to be an interesting protein marker in the milk powder sample to detect chemical modification induced by the processing/storage conditions. 相似文献
27.
28.
A. E. Asratyan M. Aderholz V. V. Ammosov W. Burkot E. F. Clayton T. Coghen O. Erriquez G. S. Gapienko V. A. Gapienko J. Guy D. Hantke G. T. Jones V. S. Kaftanov U. F. Katz J. Kern V. A. Korotkov S. P. Krutchinin M. A. Kubantsev P. Marage D. B. Miller M. M. Mobayyen D. R. O. Morrison M. Neveu J. Sacton N. Schmitz K. Varvell W. Venus W. Wittek V. G. Zaetz 《Zeitschrift fur Physik C Particles and Fields》1993,58(1):55-60
The diffractive production of charmed strangeD s * and possiblyD s mesons by neutrinos and antineutrinos on nucleons in hydrogen, deuterium and neon targets is observed. The slope parameter of thet distribution is 3.3±0.8 (GeV)?2. The production rate per charged current neutrino interaction with an isoscalar target times the D s + →φτ+ branching fraction is (1.03±0.27)×10?4. 相似文献
29.
Guy Henniart 《Inventiones Mathematicae》1993,113(1):339-350
Résumé SoitF un corps local non archimédien à corps résiduel fini. La conjecture de Langlands locale (prouvée par Laumon, Rapoport et Stuhler quandF est de caractéristique non nulle) associe à une classe d'isomorphisme de représentations irréductibles du groupe de Weil deF une classe d'isomorphisme () de représentations admissibles irréductibles supercuspidales d'un groupe linéaire surF, le groupe GL
n
(F) si est de dimensionn. Nous prouvons dans cet appendice qu'il existe au plus une telle correspondance qui préserve les facteurs de paires et coïncide, en dimension 1, avec l'application donnée par la théorie du corps de classes.
Oblatum 10 XII 1991
Un complément à l'article -elliptic sheaves and the Langlands correspondence par G. Laumon, M. Rapoport et U. Stuhler. 相似文献
Summary LetF be a non-archimedean local field with finite residue field. The local Langlands conjecture (proved by Laumon, Rapoport and Stuhler when the characteristic ofF is positive) associates to an isomorphism class of irreducible representations of the Weil group ofF an isomorphism class () of admissible irreducible supercuspidal representations of some linear group overF, viz. GL n (F) if dim ()=n. In this appendix we prove that there is at most one such correspondence which extends local class field theory in dimension 1, and preserves -factors for pairs.
Oblatum 10 XII 1991
Un complément à l'article -elliptic sheaves and the Langlands correspondence par G. Laumon, M. Rapoport et U. Stuhler. 相似文献
30.
Charge calculations in molecular mechanics. Part 8 Partial atomic charges from classical calculations 总被引:1,自引:0,他引:1
Raymond J. Abraham Guy H. Grant Ian S. Haworth Paul E. Smith 《Journal of computer-aided molecular design》1991,5(1):21-39
Summary The CHARGE2 programme, which involves the classical calculation of both the inductive and resonance contributions to the partial atomic charges in molecules is described, and the charges and electrostatic potentials obtained presented for some illustrative examples.In substituted methanes (CH3X, CF3X, CCl3X) the effects of varying the electronegativity of the substituents and the - and -substituent contributions are clearly illustrated for a variety of substituent groups X.The problems involved in the inclusion of silicon into this scheme are detailed, together with the methods of overcoming them. The partial atomic charges ( and contributions) and electrostatic potentials for some silicon oxygen compounds are presented and discussed.The partial atomic charges from CHARGE2 for all the natural amino acids as their N-acetyl, N-methyl-amides are given and compared with those obtained from the AMBER and ECEPP/2 force fields. Considerable differences in these figures are observed, with the AMBER charges consistently much larger than those from the other two methods.The CHARGE2 partial atomic charges and electrostatic potentials for the four common nucleic acids, adenine, cytosine, guanine and thymine, are given and compared with those derived from other calculations. Again there is general similarity but also there are considerable differences, with those from the AMBER force field somewhat larger than the other methods.For previous parts in this series, see Refs. 1-7. 相似文献