A MULTINUCLEAR NMR SPECTRAL STUDY OF PARENT AZOLES AND BENZAZOLES: EXPERIMENTAL RESULTS AND GIAO AB INITIO CALCULATIONS

The 13 C and 15 N chemical shifts of twelve azoles and benzazoles have been determined in the solid state at room temperature and in methanol solution at 178 K. The experimental values were compared with the absolute shieldings calculated at the GIAO/B3LYP/6-31G* level. These comparisons show that some signals, 13 C NMR but especially 15 N NMR, have to be corrected for hydrogen bonds present in certain solvents and in the solid state. The linear regressions are good enough to be used to predict some missing values.