CONDENSATION-REACTIONS OF TETRACYANOETHYLENE AND ITS MONOANION PROMOTED BY LEWIS-ACIDS - SYNTHESIS AND CRYSTAL, MOLECULAR, AND ELECTRONIC-STRUCTURE OF A NOVEL HETEROCYCLE, THE 2,3,6,7-TETRACYANO-5-(TRICYANOETHENYLIMINO)-3H-1,4,7B-TRIAZABENZO[I,J]PENTALENIDE ION

From the condensation reaction of tetracyanoethylene (C6N4, TCNE) with its radical monoanion (C6N4?-) promoted by a Lewis acid [ZnCl2, AlCl3, or V(bpy)3+2], a novel heterocyclic carbanion (C17N11-) has been synthesized and characterized by X-ray, 13C NMR, IR, and UV spectroscopy and cyclic voltammetry measurements. The crystal and molecular structure of the title anion has been determined for the tetraphenylarsonium salt, and its electronic structure and the mechanism of formation are discussed.