Spectral monitoring of tricyanovinylation of 2-phenylpyrrole and 4,5,6,7-tetrahydroindole. Self-association of the final products

Pyrroles readily and selectively react with tetracyanoethylene in DMSO yiel ding the corresponding 2-tricyanovinyl derivatives. The reaction involves i ntermediate formation of donor-acceptor pi,pi*-complex. 2-Phenyl-5-(1,2,2-t ricyanovinyl)pyrrole exists in saturated hydrocarbons as sandwich-like inte rmolecular associates; in the crystalline state, complexes with hydrogen bo nd are also formed. According to the ESR data, tricyanovinylpyrroles in cry stal give rise to radical anions via electron transfer between the componen ts of self-associates.