Two mesogenic nitrobenzoxazoles

The crystal and molecular structures of two isomeric benzoxazoles, 2-(4-nitrophenyl)benzoxazol-6-yl 4-(acryloyloxyhexyloxy)benzoate, C29H26N2O8, (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, mainly 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 two 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.