Dicyano(7,7-dimethyl-2,5-di-p-tolyl-3,4-diazabicyclo[4.1.0]hepta-2,4-dien-3-ium-3-yl)methanide and (4-benzoyl-5,5-dimethyl-2-phenyl-1-azacyclopenta-1,3-dien-1-ium-1-yl)dicyanomethanide, two stable azomethine ylides

The azomethine ylide moieties of dicyano(7,7-dimethyl-2,5-di-p-tolyl-3,4-diazabicyclo[4. 1.0]hepta-2,4-dien-3-ium-3-yl)methanide, C24H22N4, and (4-benzoyl-5,5-dimethyl-2-phenyl-1-azacyclopenta-1,3-dien-1-ium-1-yl)dicyanomethanide, C22H17N3O, show normal bond distances and angles in comparison with related structures reported previously. The dipolar N-C distances of 1.430(4) and 1.401(3)Angstrom are appreciably shortened compared with the C-N+ bond lengths [1.485(9)Angstrom] found in N-substituted pyridinium compounds, which is consistent with previous observations. Both title compounds pack in such a way that the ylide dipoles are arranged above each other but pointing in opposite directions.