Abstract
Proton nuclear magnetic resonance spectra of BF3, BCl3, and BBr3 adducts of acetonitrile have been measured in nitrobenzene solution. Single peaks were observed in each case and chemical shifts relative to tetramethylsilane decreased in the order BBr3 > BCl3 > BF3, suggesting that this is the order of acceptor activity toward acetonitrile. Linear relationships exist between methyl proton chemical shifts of CH3CNBX3 and the heats of formation, dipole moments, and infrared vibrational shifts of the same or related adducts.