STRUCTURE OF 2-HYDROXY-1-NAPHTHALDEHYDE

C11H8O2, M(r)= 172.18, monoclinic, P2(1)/n, a = 5.630 (1), h = 9.341 (2), c = 15.531 (3) angstrom, beta = 98.40 (1)-degrees, V = 808.0 (3) angstrom3, Z = 4, D(m) = 1.41 (flotation in CH3I/benzene), D(x) = 1.415 Mg m-3, lambda(Cu K-alpha) = 1.54178 angstrom, mu = 0.75 mm-1, F(000) = 360, room temperature, final R = 0.051 for 1074 observed reflections (of 1492 unique data). An intramolecular hydrogen bond is observed for the title compound with O1...O2 = 2.567 (3), H1...O2 = 1.59 (1), O1-H1 = 1.070 (6) angstrom and O1-H1...O2 = 148.9 (5)-degrees. The six-membered rings A and B of the naphthalene molecule are planar (within the 2.5-sigma range) with an angle between normals to the A and B planes of 0.38 (9)-degrees. The O1, O2, C11 and H1 atoms deviate from the best plane of the A ring by -0.036 (2), 0.029 (2), 0.035 (2) and 0.149 (5) angstrom, respectively. The H atom in the hydrogen bridge has a very large U value [0.109 (1) angstrom2] . This suggests proton motion in the asymmetric O-H-O hydrogen bridge.