Supramolecular structure of the tetrabutylammonium salt of 2-phenylpropionitrile

The deprotonation of 2-phenylpropionitrile Ph(CH3)CHCN (3) by (n-Bu)(4)N+(O H)(-) results in the corresponding tetpabutylammonium salt (4) in excellent yield. An X-ray structural analysis shows that the compound is not a genui ne carbanion ("naked anion"). Instead, a dimeric form is found in the cryst al in which the nitrogen of the cyano group in the anion undergoes multiple H-bonding with the alpha-methylene units of the (n-Bu)4N+ cations as a con sequence of CH ... N interactions. A cryoscopic study of the compound in be nzene indicates the existence of tetramers, which means that in solution su pramolecular ions pairs are involved.