Investigations of the 1J(13C1H) spin–spin coupling and 13C magnetic shielding of gaseous benzene-13C

13C NMR spectral parameters have been studied for benzene-13C in the gas phase. The solute compound was observed at low constant pressure (approx. 300 Torr) and the temperature of 298 K while xenon and carbon dioxide were used as the gaseous solvents. Complex ABB0CC0DX spectra were analyzed with the use of a PERCH program. It was found that the 13C chemical shift of benzene was linearly dependent on the solvent density. Similar dependence was also detected for the one-bond spin–spin coupling between proton and carbon nuclei, 1J(CH). For the first time the two NMR parameters for an isolated benzene molecule were obtained together with the coefficients responsible for the solute-solvent molecular interactions. q 2004 Elsevier B.V. All rights reserved.