Chloronicotinyl insecticides .8. Crystal and molecular structures of imidacloprid and analogous compounds

The crystal structures of the chloronicotinyl insecticide imidacloprid and related molecules have been determined by three-dimensional X-ray diffraction analysis. In imidacloprid the nitroimino group is coplanar with the imidazolidine ring plane; shorter ring C-N bond lengths and longer exocyclic C=N bond length were observed, suggesting a formation of a fully delocalized diene system. Similar molecular frameworks were seen in the nitromethylene and cyanoimine analogues. The interatomic distances between an imidazolidyl nitrogen and a nitro oxygen or a cyano nitrogen were ca. 5.9 Angstrom, a suitable value to bind to the recognition site on nicotinic acetylcholine receptor.