In this study, the effect of fluorine upon the heme-binding ability of the xanthone nucleus was investigated for 3, 6-bis-(ω-N, N-diethylaminoamyloxy)-4, 5-difluoroxanthone (F2C5). 2- Fluoro-1, 3-dimethoxybenzene was prepared by a new, improved method and used to build up the xanthone nucleus. The interaction of F2C5 with heme was investigated by UV–vis, 1H NMR, and 19F NMR spectroscopy. For the first time, NMR studies for the heme–drug ...