Effect of Electronic Interactions on NMR (1)J(CF) and (2)J(CF) Couplings in cis- and trans-4-t-Butyl-2-fluorocyclohexanones and Their Alcohol Derivatives

Autor(es)

Anizelli, Pedro R. ^[1] ; 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 Campinas, SP - 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: Journal of Physical Chemistry A; v. 115, n. 22, p. 5684-5692, JUN 9 2011.
• Citações Web of Science: 19

Resumo

In order to study the influence of hyperconjugative, inductive, steric, and hydrogen-bond interactions on (1)J(CF) and (2)J(CF) NMR spin-spin coupling constants (SSCCs), they were measured in cis- and trans-4-t-butyl-2-fluorocyclohexanones and their alcohol derivatives. The four isotropic terms of those SSCCs, Fermi contact (FC), spin dipolar (SD), paramagnetic spin-orbit (PSO), and diamagnetic spin-orbit (DSO), were calculated at the SOPPA(CCSD)/EPR-III level. Significant changes in FC and PSO terms along that series of compounds were rationalized in terms of their transmission mechanisms by employing a qualitative analysis of their expressions in terms of the polarization propagator formalism. The PSO term is found to be sensitive to proximate interactions like steric compression and hydrogen bonding; we describe how it could be used to gauge such interactions. The FC term of (2)J(CF) SSCC in cis- 4-t-butyl-2-fluorocyclohexanone is rationalized as transmitted in part by the superposition of the F and O electronic clouds. (AU)

• Processo FAPESP: 08/06282-0 - Estudo do mecanismo de transmissão de constantes de acoplamento escalar envolvendo o átomo de flúor
• Beneficiário: Roberto Rittner Neto
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• 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