A Novel Approach in the Determination of Magnitudes and Relative Signs of Long-Range Heteronuclear J Couplings Involving Fluorines

Abstract

Fluorine-labeled metabolic products of pesticide or drug models often involve CF3-C- moieties. The first multibond as well as direct fluorine-carbon and proton-carbon correlations are reported for several simple aliphatic fluorocarbon molecules containing CF3-C-. The relative sign and magnitude of the 19F-13C, 1H-13C, and 1H-19F coupling constants are determined with facility by the skewing and separation of multibond and direct cross peaks in the 2D heteronuclear NMR spectra. The ability to obtain the coupling information potentially provides vital clues for the structural identification of CF3-C- metabolites.