Structures and Properties of Tris(donor)-Tris(acceptor)-Substituted Benzenes, 8!!. On the Balance of Steric, Electronic and Hydrogen Bond Effects in 1,3,5-Tris(amino)-2,4,6-Tris(acceptor)-Substituted Benzenes

The conformational properties of triamino-substituted 1,3,5-trinitrobenzenes were studied by X-ray crystallography, dynamic NMR spectroscopy, and semiempirical calculations. As amino substituents all possible combinations of a dialkyl-, a monoalkylamino, and an amino group were used. All derivatives have radialene-like structures with the central six-membered ring distorted from planarity. The geometric form of the latter was linked with the electronic organization of the π system. Despite the presence of up to six intramolecular hydrogen bonds, semi-empirical calculations reproduce experimental geometries quite well.