Effect of Electronic Interactions on NMR 1JCF and 2JCF Couplings in cis- and trans-4-t-Butyl-2-fluorocyclohexanones and T

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• 作者：Pedro R. Anizelli ; Denize C. Favaro ; Rube虂n H. Contreras ; Cla虂udio F. Tormena
• 刊名：Journal of Physical Chemistry A
• 出版年：2011
• 出版时间：June 9, 2011
• 年：2011
• 卷：115
• 期：22
• 页码：5684-5692
• 全文大小：862K
• 年卷期：v.115,no.22(June 9, 2011)
• ISSN：1520-5215

文摘

In order to study the influence of hyperconjugative, inductive, steric, and hydrogen-bond interactions on ¹J_CF and ²J_CF NMR spin鈥搒pin 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鈥搊rbit (PSO), and diamagnetic spin鈥搊rbit (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 ²J_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.