Multinuclear NMR studies of gaseous and liquid sevoflurane

For the first time, a small amount of sevoflurane ((CF3)2CHOCH2F) in carbon dioxide and xenon as the gaseous solvents has been studied using 19F and 1H NMR spectra. Density-dependent 19F and 1H nuclear magnetic shielding was observed when the pressure of each solvent was increased. After extrapolation of the results to the zero-density limit it was possible to determine the appropriate shielding constants free from intermolecular interactions, σ0(F) and σ0(H). Similar procedure has also been applied for the investigation of fluorine-proton spin–spin couplings and the 2J0(FH) and 3J0(FH) constants of an isolated (CF3)2CHOCH2F molecule were also obtained. Additionally, high-resolution 1H, 13C, 17O and 19F NMR spectra of pure liquid sevoflurane were also recorded and all the 1H–13C, 1H–19F and 19F–13C spin–spin coupling constants and NMR chemical shifts were measured. It is shown that the experimental NMR parameters are suitable for comparison with the results of recent quantum-chemical calculations.