PM3 semiempirical study and its comparison with X-ray crystal structure of 4-[2-methyl-4-(4-methoxyphenylazo)] phenoxyphtalonitrile

Abstract

The molecular and crystal structures of the title compound, C22H16N4O2, were determined by single crystal X-ray diffraction technique. The title compound crystallizes in monoclinic space group P1 2 (1) /n1, with a=12.7811(9) angstrom, b=8.2002(4) angstrom, c=17.8772(14) angstrom, Z=4, D (calc)=1.3112(1) g/cm(3), mu (Mo-K-alpha)=0.087 mm(-1). The structure was solved by direct methods and refined to a final R=0.056 for 1891 reflections with I > 2 sigma (I). The asymmetric unit in the crystal structure contains only one neutral molecule. The positions of nitrogen atoms in the azo groups were disordered. There is no classic hydrogen bond in the crystal structure. The molecules in the crystal structure are stacked by pi-pi stacking and one edge-to-face interactions. In order to determine conformational flexibility and crystal packing effects on the molecules, molecular energy profile of the title compound was obtained with respect to the selected torsion angle, which is varied from -180 degrees to +180 degrees in every 10 degrees via PM3 semi-empirical method.