1H and 13C NMR study of 8‐hydroxyquinoline and some of its 5‐substituted analogues

Abstract 1H and 13C NMR spectra of 8‐hydroxyquinoline (oxine) and its 5‐Me, 5‐F, 5‐Cl, 5‐Br and 5‐NO2 derivatives have been studied in DMSO‐d6 solution. The 1H and 13C chemical shifts and proton–proton, proton–fluorine, carbon–proton and carbon–fluorine coupling constants have been determined. The 1H and 13C chemical shifts have been correlated with the charge densities on the hydrogen and carbon atoms calculated by the CNDO/2 method. The correlation of the 1H and 13C chemical shifts with the total charge densities on the carbon atoms is approximately linear (rH2 = 0.85, rC2 = 0.84). The proton in peri position to the nitro group in 5‐NO2‐oxine is an exception.