Figure 2.
(A) 1H NMR spectrum at −35 °C in THF-d8 of the reaction of 4 with FcBF4. Only the aromatic region is shown for clarity. The full spectrum is shown in Figure S19. The resonances associated only with 3 are highlighted in blue and those associated only with 5 are in red. Overlapping resonances from 3 and 5 are in purple. Asterisks indicate toluene and benzene impurities in the THF-d8. (B) Crystal structure of 5 shown as a ball and stick model. All H–atoms and the counterion are omitted for clarity.