Concerning the origin of 19F-19F NMR COSY and NOESY connections in the spectra of perfluorooctanoic acid, RF-palmitic acid-F13 and diethyl perfluorosuberate

A combination of F-19 nuclear Overhauser effects (NOE) and molecular mechanics calculations are presented for delineating the spatial origin of the well-known four-bond F-19-F-19 COSY connections which are generally observed in the F-19 NMR spectra of compounds containing perfluorinated chains. Perfluorooctanoic acid (PFOA), R-F-palmitic acid-F-13 and diethyl perfluorosuberate were used as test cases. Spin-lattice relaxation times (T-1) are included and NOESY correlations through three and four bonds occur. Copyright (c) 2005 John Wiley & Sons, Ltd.