Ein Phenyl-,,azo“-Derivat des Aeetessigsäureanilids mit zwei unterschiedlichen Konformeren im Kristallverband

Abstract

Abstract N-Phenyl-2-(2-methyl-phenylhydrazono)-3-oxobutyramide crystallizes in the monoclinic space group C2/c with 2 quite different molecules in the asymmetric unit. In one case the methylphenyl-group is twisted against the hydrazono-group by an angle of 1.7°, whereas in the other case this angle is 11.4°. The two NH-groups are involved in intramolecular hydrogen bonding with the two oxygens of the molecule. Like many other “azopigments” the molecule is the hydrazone tautomer, at least in the crystalline state. In the crystal lattice the molecules lie in layers with distances between 3.27 and 3.44 Å. Above every molecule in the layer there is a column of other molecules. The surroundings of the two different molecules in the crystal are the same. Therefore, it has to be concluded, that their differences are not a consequence of crystal forces.