Conclusions 1. The similarity of the spectra of 1 in solution and in KBr pellet indicate that the complexity of the CH region has an intramolecular, rather than an intermolecular origin. The extra bands are most likely due to resonance enhancement of a binary combination of ring modes, probably those at 1543 cm-'(in solution, 1568-1565 cm-l). A similar example of such a Fermi resonance involving C= C stretching bands has been observed for benzene." 2. ...