Multiplicity-edited heteronuclear single quantum coherence experiment modified for 19F-13C

Abstract

The popular multiplicity-edited heteronuclear single quantum coherence experiment has been modified for 19F-13C experiments by insertion of broadband inversion and refocusing pulses in 19F. This experiment has particular utility in distinguishing CF3 from CF2X, and CF2 from CFX (X = O or halide). Examples are shown of 1,1,2-trichloro-1,2,2-trifluoroethane, a mixture of 1,1,2-trichloro-1,2,2-trifluoroethane and two perfluoroolefins, and a mixture of poly(hexafluoropropylene oxide) and perfluorohexyl iodide. Phase distortions are minimized by careful selection of the value of JCF for which delays are optimized; a slight overstatement of JCF yielded no distortions, while an understatement did. Large 19F homonuclear couplings do not report cleanly in-phase. A one-dimensional version of the experiment yielded analogous editing by phase.