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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

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

Texto completo
Autor(es):
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]
Número total de Autores: 6
Afiliação do(s) autor(es):
[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
Número total de Afiliações: 5
Tipo de documento: Artigo Científico
Fonte: Journal of Molecular Structure; v. 1068, p. 170-175, JUN 25 2014.
Citações Web of Science: 6
Resumo

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)

Processo FAPESP: 12/03933-5 - Equilíbrios conformacionais e interações intramoleculares em uma série de aminoácidos: abordagem teórica e experimental
Beneficiário:Roberto Rittner Neto
Modalidade de apoio: Auxílio à Pesquisa - Regular