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 coplana r with the imidazolidine ring plane; shorter ring C-N bond lengths and longer exocyclic C=N bond length were observed, suggesting a formatio n of a fully delocalized diene system. Similar molecular frameworks we re seen in the nitromethylene and cyanoimine analogues. The interatomi c distances between an imidazolidyl nitrogen and a nitro oxygen or a c yano nitrogen were ca. 5.9 Angstrom, a suitable value to bind to the r ecognition site on nicotinic acetylcholine receptor.