STRUCTURE OF (Z,Z)-N-([2-(4-METHYLPHENYL)-2-(4-METHYLPHENYL)IMINO]ETHYLIDENE)ANILINE N-OXIDE - CONJUGATION IN SYSTEMS WITH THE NITRONE MOIETY

The crystal structure of the title compound has been determined. The crystals are orthorhombic: Pna2(1), a=8.6190(6), b=10.9705(6), c=18.7157(6)Angstrom, V=1769.7(2)Angstrom(3), Z=4. The structure was solved by direct methods and refined using 2127 reflections with F-2 greater than or equal to 2 sigma(F-2) to a final R=0.0371 and wR(F-2)=0.0865. Second-harmonic generation (SHG) activity was checked by Kurtz powder method in relation to urea. The molecule reveals the Z,Z,s-E-configuration of the 1,4-diazabutadiene fragment with a N=C-C=N torsion angle of -145.8(3)degrees. All aryl rings are twisted against each other. The crystal packing is controlled by very weak C-H...O hydrogen bonding, coupling of dipoles and weak van der Waals interactions. An influence of pi-electron conjugation on the geometry of the nitrone moiety in conjugated systems X=C-C=N-->O (X = C, N or O) is discussed.