Dynamic behaviour of fluoro‐substituted 1,8‐diarylnaphthalenes: A F-19,F-19 AND H-1,H-1 2D EXSY NMR and AM1 computational study

Interactions between polar groups and pi systems were studied for stacked aryls in 1-fluorophenyl-8-arylnaphthalenes, in which an 'electron-rich' aryl ring is forced in a stacked geometry with an 'electron-poor' fluorophenyl ring; the rotation process was examined using different NMR techniques (lineshape analysis, 2D EXSY). The Delta G(double dagger)s obtained when considering H-1 and F-19 nuclei were perfectly comparable. Semi-empirical calculations (AM1) were performed to evaluate Delta G(double dagger)s for the rotation process, and the results are compared with the experimental NMR values.