Multinuclear NMR studies of gaseous and liquid sevoflurane

Abstract For the first time, a small amount of sevoflurane ((CF 3 ) 2 CHOCH 2 F) in carbon dioxide and xenon as the gaseous solvents has been studied using 19 F and 1 H NMR spectra. Density-dependent 19 F and 1 H 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, σ 0 (F) and σ 0 (H). Similar procedure has also been applied for the investigation of fluorine-proton spin–spin couplings and the 2 J 0 (FH) and 3 J 0 (FH) constants of an isolated (CF 3 ) 2 CHOCH 2 F molecule were also obtained. Additionally, high-resolution 1 H, 13 C, 17 O and 19 F NMR spectra of pure liquid sevoflurane were also recorded and all the 1 H– 13 C, 1 H– 19 F and 19 F– 13 C 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.