PROTON MAGNETIC RESONANCE SPECTRUM OF TERMOLECULAR ORIENTED PI COMPLEX

To give evidence of localization of an acceptor in an oriented π complex, the proton magnetic resonance (pmr) spectra of the yellow toluene-ethyl fluoride-boron fluoride complex are observed at -80°. The proton resonances of the CH2F and CH3 groups in ethyl fluoride are split into the respective doublets as a result of interaction with the single 19F nucleus. The interaction shift of ethyl fluoride in a toluene solution of an un-ionized ethyl fluoride-boron fluoride complex is to lower field relative to ethyl fluoride in the pure un-ionized complex. Here an induced ring diamagnetism is absent. The observed shift is regarded as characteristic, not of a symmetrical π complex or a benzenonium ion complex, but of the oriented π complex. © 1969, American Chemical Society. All rights reserved.