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 conformation 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. This torsion angle is -23.6 (3)° for compound (1) and 32.2 (7) and -67.0 (6)° 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.

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