II-utility of fluorine-19 NMR spectroscopy for investigation of charge transfer complexes

Abstract

Fluorine and proton chemical shifts for the griseofulvin oxime—fluoranil complex are reported. ¹H, ¹⁹F-NMR spectra prove the course of the charge transfer complex formation. Due to redistribution of the electron density, the protons of the donor are slightly shifted towards a lower field where deshielding has occurred. Signals of the ¹⁹F-NMR spectra of fluoranil complex showed a positive value for the upfield shift of the fluorine resonance due to a shielding effect. Fluoranil (tetrafluoro-2,5-cyclohexadiene-1,4-dione) has a high electron-accepting ability with respect to the functional groups containing heteroatoms. The complete qualitative and quantitative chemical characterization of the resulting complex has been studied.