The 15-crown-5 complex of the sodium salt of 2-nitroimidazole has been
isolated and its solid state structure determined by X-ray crystallog
raphy. This shows bonding interactions between the sodium atom and the
imidazolate through a ring nitrogen and one of the nitro-oxygen atoms
. The sodium ion is seven co-ordinate and is located slightly out of t
he least-squares plane of the crown ether. In solution, the complex ac
ts as a naked anion allowing the heterocyclic ring to be N-alkylated u
nder mild conditions. (C) 1997 Published by Elsevier Science Ltd.