Experimental

R factor = 0.049; wR factor = 0.130; data-to-parameter ratio = 13.1. In the title compound, C18H12F3NO2, the planes of the benzene ring and the naphthalene system form a dihedral angle of 47.21 (3). The hydroxy group is involved in an intramolecular O—H N hydrogen bond. In the crystal, weak C—H O and C—H F interactions link the molecules related by translations along the c and a axes, respectively, into sheets. Related literature For background to photochromic and thermochromic char-acteristics and tautomerism of Schiff bases, see: Cohen et al. (1964); Hadjoudis et al. (1987). For related structures, see: Gül et al. (2007); Yüce et al. (2004). For classification of hydrogen