2 MESOGENIC NITROBENZOXAZOLES

The crystal and molecular structures of two isomeric benzoxazoles, 2-( 4-nitrophenyl)benzoxazol-6-yl 4-(acryloyloxyhexyloxy)benzoate, C29H26N 2O8, (1), and 4-(6-nitro-2-benzoxazolyl)phenyl 4-(acryloyloxyhexyloxy) benzoate, C29H26N2O8, (2), are reported. Both compounds are mesogenic and are of potential interest for non-linear optics. Some differences in the molecular conformations of the two compounds are observed, main ly in the torsion angle around the bond from the aromatic C to ester O atoms and in the dihedral angle between the planes of the benzoxazole system and the phenyl group attached to it. The torsion angle is -23. 6(3)degrees for compound (1) and 32.2(7) and -67.0(6)degrees for the t wo independent molecules of (2). These differences, which are probably due to packing effects, do not affect the pattern of bond lengths and angles within the molecules to any significant extent.