An NMR and Quantum Mechanical Investigation of Solvent Effects on Conformational Equilibria of Butanedinitrile

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• 作者：David R. Kent ; IV ; Neelendu Dey ; Fredric Davidson ; Franç ; oise Gregoire ; Krag A. Petterson ; William A. Goddard ; III ; and John D. Roberts
• 刊名：Journal of the American Chemical Society
• 出版年：2002
• 出版时间：August 7, 2002
• 年：2002
• 卷：124
• 期：31
• 页码：9318 - 9322
• 全文大小：80K
• 年卷期：v.124,no.31(August 7, 2002)
• ISSN：1520-5126

文摘

Vicinal proton-proton NMR couplings and ab initio quantum mechanics have been used toinvestigate solvent effects on conformational equilibria of butanedinitrile. The trans and gauche conformationsare about equally favored at room temperature in solvents of low dielectric constant while the equilibriumis essentially the statistical proportions of one-third trans and two-thirds gauche in water with a high dielectricconstant. The coupling assignments were confirmed with the aid of stereospecific deuterium-labeled (R,Ror S,S)-1,2-dideuteriobutanedinitrile. The calculations support the observed trends. Similar results wereobserved for 1,2-dibromo- and dichloroethanes.