Conformational analysis of 2-bromocyclohexanone. A combined NMR, IR, solvation and theoretical approach

dc.creatorFreitas, MP
dc.creatorRittner, R
dc.creatorTormena, CF
dc.creatorAbraham, RJ
dc.date2001
dc.dateJUN
dc.date2014-11-17T13:18:11Z
dc.date2015-11-26T16:43:22Z
dc.date2014-11-17T13:18:11Z
dc.date2015-11-26T16:43:22Z
dc.date.accessioned2018-03-28T23:28:23Z
dc.date.available2018-03-28T23:28:23Z
dc.identifierJournal Of Physical Organic Chemistry. John Wiley & Sons Ltd, v. 14, n. 6, n. 317, n. 322, 2001.
dc.identifier0894-3230
dc.identifierWOS:000169008500001
dc.identifier10.1002/poc.373
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/56504
dc.identifierhttp://www.repositorio.unicamp.br/handle/REPOSIP/56504
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/56504
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1273568
dc.descriptionAn improved method of conformational analysis using H-1 and C-13 NMR, IR, theoretical calculations and solvation theory is reported for 2-bromocyclohexanone, used here as a model compound. The solvent dependence of the (3)J(HH), (1)J(CH) and (1)J(CD) NMR coupling constants and the associated changes in the IR first overtone carbonyl band intensities together with theoretical calculations allow the direct determination of the conformational equilibria without recourse to model compounds. Calculations with the Gaussian 98 program at the HF/6-31 g(d,p) and B3LYP/6-31 + g(d,p) levels together with solvation theory gave the conformer free energy difference (E-eq - E-ax) in different solvents. The observed couplings, when analyzed by solvation theory and utilizing DFT geometries, gave a value of E-eq - E-ax of 1.15 kcal mol(-1) in the vapor phase, decreasing to 0.6 kcal mol(-1) in CCl4 and to -0.5 kcal mol(-1) in DMSO solution (1 kcal = 4.184 kJ). The axial percentage changes from 74% (in CCl4) to 30% (in DMSO), and these are in good agreement with infrared data (nu (C=O), first overtone), despite the uncertainties of the latter method. The results illustrate the advantages of the joint application of these techniques, which represents an improved approach to the study of the conformational equilibria of substituted cyclohexanones. Copyright (C) 2001 John Wiley & Sons, Ltd.
dc.description14
dc.description6
dc.description317
dc.description322
dc.languageen
dc.publisherJohn Wiley & Sons Ltd
dc.publisherW Sussex
dc.publisherInglaterra
dc.relationJournal Of Physical Organic Chemistry
dc.relationJ. Phys. Org. Chem.
dc.rightsfechado
dc.rightshttp://olabout.wiley.com/WileyCDA/Section/id-406071.html
dc.sourceWeb of Science
dc.subject2-bromocyclohexanone
dc.subjectconformational analysis
dc.subjectNMR
dc.subjectIR
dc.subjectsolvation
dc.subjectdensity functional theory
dc.subjectCoupling-constants
dc.subjectOrganic-molecules
dc.subjectIsomerism
dc.titleConformational analysis of 2-bromocyclohexanone. A combined NMR, IR, solvation and theoretical approach
dc.typeArtículos de revistas


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