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-trinitrobe nzenes were studied by X-ray crystallography, dynamic NMR spectroscopy , and semiempirical calculations. As amino substituents all possible c ombinations of a dialkyl-, a monoalkylamino, and an amino group were u sed. All derivatives have radialene-like structures with the central s ix-membered ring distorted from planarity. The geometric form of the l atter was linked with the electronic organization of the pi system. De spite the presence of up to six intramolecular hydrogen bonds, semi-em pirical calculations reproduce experimental geometries quite well.