Selective detection of the proton NMR spectra of molecules containing rare spins at natural abundance in liquid crystalline samples

It is shown that the proton NMR spectra of molecules containing rare spins at natural abundance dissolved in a liquid crystalline solvent can be obtained free from the strong lines from the spectrum of the abundant isotopomer by the 2D HSQC NMR experiment. The technique can also give the individual chemical shifts of the rare spins, and, for a molecule containing another abundant nucleus, such as fluorine, the rare spin--(19)F total anisotropic couplings are also obtained. The usefulness of the technique is demonstrated for molecules containing (13)C as the rare spins.