Relações lineares múltiplas entre deslocamentos químicos em RMN 13C de haletos alifáticos
Article Sidebar
Main Article Content
Abstract
Os deslocamentos químicos de RMN 13C de carbonos a , b , g e d de 17 conjuntos de haletos (F, Cl Br e I) alifáticos, inclusive compostos mono, bi e tricíclicos, podem ser reproduzidos por uma equação linear de duas constantes e duas variáveis do tipo : d R-X = A*d R-X1 + B*d R-X2 onde A e B são constantes obtidas por regressão multilinear a partir de deslocamentos químicos de 13C; d R-X, o deslocamento químico de 13C do composto com halogênio (R-X); d R-X1 e d R-X2 deslocamentos químicos de outros haletos. Para brometos (R-X) alifáticos a melhor correlação foi obtida com os dados de fluoretos (R-X1) e iodetos (R-X2) com R2 de 0,9989 e desvio médio absoluto (DM) de 0,39ppm. Para cloretos (R-X) a melhor correlação foi com dados de brometos (R-X1) e iodetos (R-X2) com R2 de 0,9960 e DM de 0,76ppm. Para fluoretos (R-X) a melhor correlação foi com brometos (R-X1) e iodetos (R-X2) com R2 de 0,9977 e DM de 1,10ppm e para iodetos (R-X) foi com fluoretos (R-X1) e brometos (R-X2) com R2 de 0,9972 e desvio médio absoluto de 0,60 ppm.
Metrics
Article Details
This work is licensed under a Creative Commons Attribution 4.0 International License.
The corresponding author transfers the copyright of the submitted manuscript and all its versions to Eclet. Quim., after having the consent of all authors, which ceases if the manuscript is rejected or withdrawn during the review process.
When a published manuscript in EQJ is also published in other journal, it will be immediately withdrawn from EQ and the authors informed of the Editor decision.
Self-archive to institutional, thematic repositories or personal webpage is permitted just after publication. The articles published by Eclet. Quim. are licensed under the Creative Commons Attribution 4.0 International License.
References
BUCCI, P., Tentative interpretation of 13C and 1H NMR chemical shifts in simple methyl and ethyl derivatives, J. Am. Chem. Soc.(Easton), v.90, p.252-254, 1968.
DOYAMA, J. T., Estudo dos efeitos de alguns substituintes em RMN de 13C, São Paulo, 1989, 74p. Dissertação (Mestrado em Química Orgânica) – Instituto de Química Universidade de São Paulo.
EGGERT, H., VanANTWERP, L. C., BHACCA, S. N., DJERASSI, C., Carbon-13 nuclear magnetic resonance spectra of hydroxy steroids, J. Org. Chem.(Washington), v.41, p.71-78, 1976.
EJCHART, A.,Substituent effects on 13C NMR chemical shifts in the saturated framework of primary aliphatic derivatives, Org. Magn. Reson.(London), v.13 p.368-371, 1980.
EJCHART, A., Substituent effects on 13C NMR 2. chemical shifts in the saturated framework of secondary aliphatic derivatives Org. Magn. Reson.(London), v.15 p.22-24, 1981.
GRANT, D. M., PAUL, E. G., Carbon 13 magnetic resonance II. chemical shift data for the alkanes, J. Am. Chem. Soc.(Easton), v.86, p.2984-90, 1964.
JAIME, C., Empirical computation of 13C NMR chemical shifts, Magn. Reson. Chem.(London), v.28, p.42-46, 1990.
LITCHMAN, W. M., GRANT, D. M., Carbon-13 magnetic resonance structural and eletronic effects on the carbon-13 nuclear magnetic resonance spectra of the halogen-substituted methanes, J. Am. Chem. Soc.(Easton), v.90, p.1400-1405, 1968.
RITTNER, R. e BRAIBANTE M. E.F., Carbon-13 NMR chemical shift substituent effects 8- 3- monosubstituted 2-methylpropenes, Magn. Reson. Chem.(Easton), v.30, p.420-424, 1992.
ROBERTS, J. D., WEIGERT, F. J., KROSHWITZ, J. I., REICH, J. J., Nuclear magnetic resonance spectroscopy. carbon-13 chemical shifts in acyclic and alicyclic alcohols J. Am. Chem. Soc.(Easton), v.92, p.1338-47, 1970.
SCHNEIDER, H. J., GSCHWENDTNER, W., Polar and steric long-range transmission effects in cholestanes cholestenes, and 9-substituted decalins. Carbon-13 nuclear magnetic resonance shifts and force field and linear eletric field calculation, J. Org. Chem.(Washington), v.47, p.4216-4221, 1982.
SURYANARAYANA, I., GASTEIGER, J., A quantitative empirical treatment of 13C NMR chemical shifts variation an successive substitution of methane by halogen atoms, Magn. Reson. Chem. (London), v.23, p.156-157, 1985.
SURYANARAYANA, I., GASTEIGER, J., Quantitative empirical treatment of 13C NMR chemical shifts of aliphatic halides, Magn. Reson. Chem.(London), v.29, p.975-984, 1991.
WILBERG, K. B., PRATT, W. E., BAILEY, W. F., Nature of substituent effects in NMR spectroscopy 1. Factor analysis of carbon-13 chemical shifts in aliphatic halides, J. Org. Chem.(Washington), v.45, P.4936-47, 1980.