Carbon–fluorine two-dimensional NMR correlation spectra

Direct detection heteronuclear correlation (HETCOR) 13C{19F} and indirect detection gHMQC and gHSQC 19F{13C} two-dimensional correlation spectra have been compared for 1,3-perfluoro dimethylcyclohexane. Correlations to the geminally non-equivalent fluorine atoms in the CF2 groups are more difficult to unambiguously observe using gHMQC or HETCOR in this typical cyclic fluorochemical in which 2JFF ∼ > 1JCF, but they are readily observed and assigned in the gHSQC experiment. Excellent 2D gHSQC 19F{13C} correlation spectra have also been obtained on H(CF2)4CH2OH without proton decoupling, although half of the correlations within the several FH multiplets have zero intensity.