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 ²J_FF ∼ > ¹J_CF, 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.