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61.
Goetz AE Bronner SM Cisneros JD Melamed JM Paton RS Houk KN Garg NK 《Angewandte Chemie (International ed. in English)》2012,51(11):2758-2762
Think before you act: a computational approach is reported for evaluating the synthetic potential of heterocyclic arynes. Routine and rapid calculations of arene dehydrogenation energies and aryne angle distortion predict the likelihood that a given hetaryne can be generated, as well as the degree of regioselectivity expected in a reaction between a given hetaryne and a nucleophilic trapping agent. 相似文献
62.
Andrew S. Paton Alan J. Lough Timothy P. Bender 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(11):o459-o464
The crystal structures of three sulfonate pseudohalide derivatives of boron subphthalocyanine (BsubPc) are described and compared with four structures of three published sulfonate derivatives. Benzenesulfonate boron subphthalocyanine [(benzenesulfonato)(subphthalocyaninato)boron, C30H17BN6O3S, (I)] crystallizes in the space group P with Z = 2. The structure contains two centrosymmetric π‐stacking interactions between the concave faces of the isoindoline units in the BsubPc ligands. 3‐Nitrobenzenesulfonate boron subphthalocyanine [(3‐nitrobenzenesulfonato)(subphthalocyaninato)boron, C30H16BN7O5S, (II)] crystallizes in the space group P21/c with Z = 4. The structure contains an intermolecular S—O...π interaction from the sulfonate group to a five‐membered N‐containing ring of an isoindoline unit on the concave side of a neighbouring BsubPc ligand, at a distance of 3.151 (3) Å. The crystal of methanesulfonate boron subphthalocyanine [(methanesulfonato)(subphthalocyaninato)boron, C25H15BN6O3S, (III)] was produced via sublimation and it is not a solvate, in contrast with two previously published structures of the same compound. Compound (III) crystallizes in the space group P21/n with Z = 2, and its structure is similar to that of the more common compound Cl‐BsubPc. 相似文献
63.
Alison J. Fugard Antti S. K. Lahdenper Jaqueline S. J. Tan Aroonroj Mekareeya Robert S. Paton Martin D. Smith 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(9):2821-2824
Non‐biaryl atropisomers are valuable in medicine, materials, and catalysis, but their enantioselective synthesis remains a challenge. Herein, a counterion‐mediated O‐alkylation method for the generation of atropisomeric amides with an er up to 99:1 is outlined. This dynamic kinetic resolution is enabled by the observation that the rate of racemization of atropisomeric naphthamides is significantly increased by the presence of an intramolecular O?H???NCO hydrogen bond. Upon O‐alkylation of the H‐bond donor, the barrier to rotation is significantly increased. Quantum calculations demonstrate that the intramolecular H‐bond reduces the rotational barrier about the aryl–amide bond, stabilizing the planar transition state for racemization by approximately 40 kJ mol?1, thereby facilitating the observed dynamic kinetic resolution. 相似文献
64.
65.
A gas chromatographic separation of dihydroxy- from monohydroxycannabinoids by the use of homologous trialkylsilyl derivatives is discussed. Trimethylsilyl derivatives produced a group of peaks containing both sets of compounds, sometimes poorly resolved, whereas by increasing the alkyl chain length to n-butyl complete fractionation into two groups, was achieved. The mass spectra of these derivatives resembled those of the trimethylsilyl derivatives with the addition of a set of ions resulting from estimation of the Si-alkyl chains as olefins. 相似文献
66.
67.
J. R. Allan A. D. Paton M. J. Pendlowski 《Journal of Thermal Analysis and Calorimetry》1985,30(3):579-586
Some complexes of the thiocyanates, chlorides and bromides of cobalt(II), nickel(II) and copper(II) with 3-picolylamine have been prepared. The stereochemical configurations of the complexes were deduced using spectral and magnetic properties. The decomposition of the complexes was studied by thermogravimetry and differential thermal analysis.
Zusammenfassung Einige Komplexe der Thiocyanate, Chloride und Bromide von Kobalt(II) und Kupfer(II) mit 3-Picolylamin wurden hergestellt. Die stereochemischen Konfigurationen der Komplexe wurden aus den spektralen und magnetischen Eigenschaften abgeleitet. Die Zersetzung der Komplexe wurde thermogravimetrisch und differentialthermoanalytisch untersucht.
, , 3-. . .相似文献
68.
Shifts δH in hadronic levels are produced by coupling to real or virtual decay channels. Using the P-matrix formalism, a simple approximate expression for δH is obtained. An application is made to the Δ-multiplet. 相似文献
69.
Unitarity effects of multiparticle channels on elastic scattering are studied schematically in the dual model. Explanations are offered for (A) the difference in energy dependence between ‘Pomeron’ and isospin exchanges, (B) the difference in the slopes of diffraction peaks for exotic and non exotic reactions, and (C) the ‘cross-over’ phenomenon. 相似文献