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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

C-13 NMR: (n)J(CH) and (1)J(CC) scalar spin-spin coupling constants (SSCCs) for some 3-monosubstituted 2-methylpropenes

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Author(s):
Schuquel, Ivania T. A. [1] ; Ducati, Lucas C. [2] ; Tormena, Claudio F. [3] ; de Freitas, Matheus P. [4] ; de Kowalewski, Dora G. [5] ; Rittner, Roberto [3]
Total Authors: 6
Affiliation:
[1] Univ Estadual Maringa, Dept Chem, BR-87020970 Maringa, Parana - Brazil
[2] Univ Sao Paulo, Inst Chem, BR-05513970 Sao Paulo - Brazil
[3] Univ Estadual Campinas, Inst Chem, BR-13083970 Campinas, SP - Brazil
[4] Univ Fed Lavras, Dept Chem, BR-37200000 Lavras, MG - Brazil
[5] Univ Buenos Aires, FCEyN, Dept Phys, Buenos Aires, DF - Argentina
Total Affiliations: 5
Document type: Journal article
Source: Journal of Molecular Structure; v. 1068, p. 170-175, JUN 25 2014.
Web of Science Citations: 6
Abstract

Twelve methallylic derivatives were studied using C-13 NMR spectroscopy and theoretical calculations. Theoretical coupling constants were obtained with SOPPA (CCSD). All atoms were described by the EPR-III basis set, except for halogens, which were represented by the cc-pVTZ basis set. Geometries were optimized at the MP2/aug-cc-pVTZ level of theory, confirming previous results that the gauche and s-cis conformers predominate. Experimental (n)J(CH) coupling constants were determined from coupled C-13 NMR spectra, while the (1)J(CC) couplings were measured through the INADEQUATE technique. The experimental and theoretical values were in good agreement. Correlations with the usual substituent physicochemical parameters indicated that the (1)J(C3Hc) values (where Hc is attached to the C3 carbon bearing the substituent) exhibit good correlations with Taft's sigma (sigma(1) inductive parameter) and the Swain-Lupton Field Effect (F) (R similar to 0.957), while other correlations were not similarly significant (R values <0.9). (C) 2014 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 12/03933-5 - Conformational equilibria and intramolecular interactions for a series of amino-acids: theoretical and experimental approaches
Grantee:Roberto Rittner Neto
Support Opportunities: Regular Research Grants