Abstract: Conclusive evidence is presented to rule out ionization as the process responsible for the dynamic nmr behavior of 9-arylfluorenes, in which rotation about the aryl-Cs bond is hindered. The observation of separate resonances for the diastereotopic isopropyl methyl groups of 2-(2-propyl)-9-mesityl-9-fluorenol (6b) and 2-(2-propyl)-9-mesityl-9-chlorofluorene (612) under conditions of rapid exchange of the mesityl methyl groups excludes any ...
