No abstract is provided for this article.
A free energy of hydration profile for the Claisen rearrangement of allyl vinyl ether (AVE) has been obtained from Monte Carlo statistical mechanics simulations at 25 °C. The gas-phase minimum energy reaction path through the chair transition state was determined from ab initio 6-31G(d) calculations and was followed in a periodic cell containing 838 water molecules. The transition state is computed to be 3.85 ± 0.16 kcal/mol better hydrated than the reactant, which corresponds to a rate increase by a factor of 664 over the gas-phase reaction. This large effect is shown to be consistent with available experimental data. The origin of the effect is analyzed. The energetic impact of multiple conformational states for the reactant has also been considered.
No abstract is provided for this article.
No abstract is provided for this article.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical consequences of orbital interactions. 3. Energetic impact of monohomoaromaticityWilliam L. JorgensenCite this: J. Am. Chem. Soc. 1976, 98, 22, 6784–6789Publication Date (Print):October 1, 1976Publication History Published online1 May 2002Published inissue 1 October 1976https://pubs.acs.org/doi/10.1021/ja00438a002https://doi.org/10.1021/ja00438a002research-articleACS PublicationsRequest reuse permissionsArticle Views112Altmetric-Citations43LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Die Baeyer‐Vil1iger‐Oxidation der Ether (1) zu den Lactonen (II) wird untersucht.
No abstract is provided for this article.
Sampling procedures for enhancing the convergence of Monte Carlo simulations of dilute solutions have been analyzed and applied to modeling n-butane in a Lennard-Jones liquid at 25 °C. The efficiency of the procedures is compared for determining structural and thermodynamic properties of the solution including the trans–gauche equilibrium for the solute. Preferential sampling of the solute plus umbrella sampling with ’’chopped’’ rotational barriers is found to be a viable means for studying conformational equilibria in solution.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolvent effects on a Diels-Alder reaction from computer simulationsJames F. Blake and William L. JorgensenCite this: J. Am. Chem. Soc. 1991, 113, 19, 7430–7432Publication Date (Print):September 1, 1991Publication History Published online1 May 2002Published inissue 1 September 1991https://pubs.acs.org/doi/10.1021/ja00019a055https://doi.org/10.1021/ja00019a055research-articleACS PublicationsRequest reuse permissionsArticle Views1295Altmetric-Citations200LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
Ab initio molecular orbital calculations are being used to study the reactions of anionic nucleophiles with carbonyl compounds in the gas phase. A rich variety of energy surfaces is found as shown here for reactions of hydroxide ion with methyl formate and formaldehyde, chloride ion with formyl and acetyl chloride, and fluoride ion with formyl fluoride. Extension of these investigations to determine the influence of solvation on the energy profiles is also underway; the statistical mechanics approach is outlined and illustrated by results from Monte Carlo simulations for the addition of hydroxide ion to formaldehyde in water.
Monte Carlo statistical mechanics simulations have been carried out for Cl− and Na+ in clusters of 1–14 water molecules. OPLS potential functions were used including the TIP4P model of water that do not include explicit polarization effects. In contrast to a prior report with the same potential functions, the computed enthalpies of binding for Cl− are shown to agree closely with experimental data, while the values for Na+ are about 10% too exothermic. The latter discrepancy is largely removed by using Aqvist’s Na+ parameters with TIP3P water. Moreover, the structures of the clusters show the expected nonspherical distribution of water molecules.
