Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/66402
Type: Artigo de periódico
Title: Experimental, SOPPA(CCSD), and DFT Analysis of Substitutent Effects on NMR (1)J(CF) Coupling Constants in Fluorobenzene Derivatives
Author: Vilcachagua, JD
Ducati, LC
Rittner, R
Contreras, RH
Tormena, CF
Abstract: Interesting insight into the electronic molecular structure changes associated with substituent effects on the Fermi contact (FC) and paramagnetic spin-orbit (PSO) terms of (1)J(CF) NMR coupling constants (SSCCs) in o-X-, m-X-, and p-X-fluorobenzenes (X = NH2; NO2) is presented. The formulation of this approach is based on the influence of different conjugative and hyperconjugative interactions on a second-order property, which can be qualitatively predicted if it is known how they affect the main virtual excitations entering into that second-order property. A set of consistent approximations are introduced in order to analyze the behavior of occupied and virtual orbitals, which define some experimental trends for (1)J(CF) spin-spin coupling constants. In addition, DFT hybrid functionals were used, and a similar degree of confidence to compute the (1)J(CF) with those observed for the SOPPA(CCSD) method was obtained. The (1)J(CF) SSCCs for ezetimibe, a commercially fluorinated drug used to reduce cholesterol levels, were measured and DFT-calculated, and the qualitative approach quoted above was applied. As a byproduct, a possible method to determine experimentally a significant PSO contribution to (1)J(CF) SSCCs is discussed.
Country: EUA
Editor: Amer Chemical Soc
Rights: fechado
Identifier DOI: 10.1021/jp110290b
Date Issue: 2011
Appears in Collections:Unicamp - Artigos e Outros Documentos

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