The electronic origin of unusually large (n)J(FN) coupling constants in some fluoroximes

Autor(es)

Favaro, Denize C. ^[1] ; Contreras, Ruben H. ^{[2, 3]} ; Tormena, Claudio F. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Inst Chem, BR-13084971 Sao Paulo - Brazil

^[2] Consejo Nacl Invest Cient & Tecn, IFIBA, RA-1033 Buenos Aires, DF - Argentina

^[3] Univ Buenos Aires, FCEyN, Dept Phys, Buenos Aires, DF - Argentina

• Tipo de documento: Artigo Científico
• Fonte: Magnetic Resonance in Chemistry; v. 51, n. 6, p. 334-338, JUN 2013.
• Citações Web of Science: 6

Resumo

SOPPA(CCSD) calculations show that the FC term is the most important contribution to the through-space transmission of J(FN) coupling constants for the fluoroximes studied in this work. Because of the well-known behavior of FC term, a new rationalization for the experimental (TS)J(FN) SSCC is presented. It is mainly based on the overlapmatrix (S-ij) between fluorine and nitrogen lone pairs obtained from NBO analyses. An expression is proposed to take into account the influence of the electronic density (D-ij) between coupled nuclei as well as the s% character at the site of the coupling nuclei of bonds and non-bonding electron pairs involved in D-ij. In using this approach, a linear correlation between (TS)J(FN) versus D-ij is obtained. The most important aspect of this rationalization is related to the facility for understanding the behavior of some unusual experimental coupling constants. It is shown that, at least in this case, the electronic origin of the so-called through-space coupling is transmitted through to the overlap of orbitals on the coupled atoms, suggesting that, at least for these compounds, instead of through-space coupling, it should better be dubbed as `through overlapping orbital coupling'. Copyright (C) 2013 John Wiley \& Sons, Ltd. (AU)

• Processo FAPESP: 10/10993-9 - Estudo do mecanismo de transmissão de constantes de acoplamento escalar através do espaço
• Beneficiário: Claudio Francisco Tormena
• Modalidade de apoio: Auxílio à Pesquisa - Regular