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51.
James E. Jackson George B. Mock Merry L. Tetef Guo-xiu Zheng Maitland Jones 《Tetrahedron》1985,41(8):1453-1464
Dicarbomethoxycarbene and dichlorocarbene add to 1,2,2-trimethylbicyclo[1.1.0]butanc in such a fashion as to suggest a concerted addition in which the central and side bonds are cleaved simultaneously. MNDO calculations support such a pathway and suggest that endo attack on the bicyclobutane is preferred to exo. Reaction of the same two carbenes with quadricyclane gives substituted derivatives of the exo-tricyclo[3.2.1.02,4]oct-6-ene system. Although these products rearrange further under the conditions of reaction and/or analysis, they can be shown to be primary products. It is suggested that quadricyclane reacts with carbenes in a concerted fashion. 相似文献
52.
53.
Papri Bhattacharya Zachariah M. Heiden Geoffrey M. Chambers Samantha I. Johnson R. Morris Bullock Michael T. Mock 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(34):11744-11750
Catalysts for the oxidation of NH3 are critical for the utilization of NH3 as a large‐scale energy carrier. Molecular catalysts capable of oxidizing NH3 to N2 are rare. This report describes the use of [Cp*Ru(PtBu2NPh2)(15NH3)][BArF4], (PtBu2NPh2=1,5‐di(phenylaza)‐3,7‐di(tert‐butylphospha)cyclooctane; ArF=3,5‐(CF3)2C6H3), to catalytically oxidize NH3 to dinitrogen under ambient conditions. The cleavage of six N?H bonds and the formation of an N≡N bond was achieved by coupling H+ and e? transfers as net hydrogen atom abstraction (HAA) steps using the 2,4,6‐tri‐tert‐butylphenoxyl radical (tBu3ArO.) as the H atom acceptor. Employing an excess of tBu3ArO. under 1 atm of NH3 gas at 23 °C resulted in up to ten turnovers. Nitrogen isotopic (15N) labeling studies provide initial mechanistic information suggesting a monometallic pathway during the N???N bond‐forming step in the catalytic cycle. 相似文献
54.
Michael M. Coleman Marissa Mock Paul C. Painter 《Journal of Macromolecular Science: Physics》2013,52(4):403-417
Oxidation reactions are one of the main reasons for the failure of polymeric materials. Antioxidants, compounds designed to protect against oxidation, must meet three main requirements for success: (1) an efficient antioxidative mechanism, (2) compatibility with the oxidizing polymer, and (3) permanence Within the oxidizing polymer. Common antioxidants are low molecular weight materials that can easily diffuse, leach, or evaporate from the polymer they are designed to protect. An increase in the molecular weight of the antioxidant not only decreases diffusion and volatility, but also decreases compatibility since most high molecular weight polymers will not mix. Selective sterically hindered phenolics, however, are concurrently antioxidants and “compatibilizers” through hydrogen bond formation. Carefully designed copolymers containing a small percentage of 2,6-diisopropyl-4-vinylphenol were found to mix intimately with two readily oxidizing polyethers and to protect them against oxidation. 相似文献
55.
Ina Puscasu Christian Mock Michael Rauterkus Axel Rndigs Gesche Tallen Suman Gangopadhyay Johannes E. A. Wolff Bernt Krebs 《无机化学与普通化学杂志》2001,627(6):1292-1298
The reactions of [Pt(dpma)(H2O)2]2+ (dpma = 2,2′‐dipyridylmethylamine) and [Pt(dpk)(H2O)2]2+ (dpk = 2,2′‐dipyridylketone) with the model nucleobases 1‐methylthymine (1‐MeT) and 1‐methyluracil (1‐MeU) were studied. Reaction products were characterized by 195Pt NMR spectroscopy and by X‐ray structure analysis. The symmetric dpma and dpk diaqua complexes form dinuclear complexes with 1‐methylthymine, acting as secondary bridging ligand via its N3 and O4 donor atoms. [Pt2(dpma)2(1‐MeT)2](ClO4)2 · H2O ( 5 ) and [Pt2(dpk)(dpk · H2O)(1‐MeT)2](PF6)2 · 4 H2O ( 6 ) both show a head‐to‐head arrangement. Biological tests show a significant in vitro antitumor activity of [Pt(dpk)Cl2] against the human glioma cell line U 87. 相似文献
56.
Allan F Mock Jessica L Richardson Jui-Yi Hsieh Gina Rinetti Diane M Papazian 《BMC neuroscience》2010,11(1):99
Background
The zebrafish has been suggested as a model system for studying human diseases that affect nervous system function and motor output. However, few of the ion channels that control neuronal activity in zebrafish have been characterized. Here, we have identified zebrafish orthologs of voltage-dependent Kv3 (KCNC) K+ channels. Kv3 channels have specialized gating properties that facilitate high-frequency, repetitive firing in fast-spiking neurons. Mutations in human Kv3.3 cause spinocerebellar ataxia type 13 (SCA13), an autosomal dominant genetic disease that exists in distinct neurodevelopmental and neurodegenerative forms. To assess the potential usefulness of the zebrafish as a model system for SCA13, we have characterized the functional properties of zebrafish Kv3.3 channels with and without mutations analogous to those that cause SCA13. 相似文献57.
Alber T Appelshäuser H Bächler J Bartke J Bialkowska H Bieser F Bloomer MA Blyth CO Bock R Bormann C Brady FP Brockmann R Buncic P Caines HL Cebra D Chan P Cooper GE Cramer JG Cramer PB Csato P Derado I Dunn J Eckardt V Eckhardt F Euler S Ferguson MI Fischer HG Fodor Z Foka P Freund P Fuchs M Gal J Gazdzicki M Gladysz E Grebieszkow J Günther J Harris JW Heck W Hegyi S Hill LA Huang I Howe MA Igo G Irmscher D Jacobs P Jones PG Kadija K Kecskemeti J Kowalski M Kühmichel A Lasiuk B Margetis S 《Physical review letters》1995,75(21):3814-3817
58.
M. S. Mock 《Numerische Mathematik》1974,23(1):37-46
A class of singular second order nonlinear two-point boundary value problems is solved, by introducing a finite element approximation which preserves an assumed monotonicity condition in the discrete equations obtained. 相似文献
59.
Mock S Shen X Tamvakopoulos C 《Rapid communications in mass spectrometry : RCM》2002,16(22):2142-2147
A method is described for the determination of melanotan-II (MT-II), a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (alpha-MSH), in rat plasma by liquid chromatography/tandem mass spectrometry (LC/MS/MS). The analyte is recovered from plasma by solid-phase extraction (SPE) and subsequently analyzed by LC/MS/MS. A SPE procedure using OASIS 96-well plates is used for extraction of MT-II from rat plasma. Using the described approach a limit of quantitation of 5 ng/mL was achieved in rat plasma. This level of sensitivity allowed the determination of pharmacokinetic parameters, following intravenous administration of MT-II in rat. 相似文献
60.
Jürgen Bokowski Simon King Susanne Mock Ileana Streinu 《Discrete and Computational Geometry》2005,33(4):645-668
We present a new proof of the Topological Representation Theorem for
oriented matroids in the general rank case. Our proof is based on an
earlier rank 3 version. It uses hyperline sequences and the
generalized Schonflies theorem. As an application, we show that one can read off oriented matroids
from arrangements of embedded spheres of codimension one, even if wild
spheres are involved. 相似文献