An IR, NMR, dipole moment and X-ray study on intramolecular O-H N hydrogen bonding in 8-hydroxy-N,N-dimethyl-1-naphthylamine

The X-ray diffraction structure at 85 K and physico-chemical properties of 8-hydroxy-N,N-dimethyl-1-naphthylamine have been studied. Five crystallographically independent molecules, of which two are disordered, are contained in the centrosymmetric triclinic unit cell of dimensions: a = 10.307(9), b = 13.459(9), c = 19.183(9) Angstrom, a = 93.98(6), beta = 102.91(6), gamma = 97.05(9)degrees, V = 2561(3) Angstrom(3). For the non-disordered molecules the mean length of the intramolecular O-H ... N hydrogen bond is 2.569(5) Angstrom and the H atom position is described by the 0.90(3) and 1.72(3) Angstrom mean distance for O-H and H ... N, respectively. Two of the crystallographically independent molecules are joined by a weak, bifurcated O-H ... O hydrogen bond with O ... O distance of 2.878(2) Angstrom. The studies of H-1 NMR, IR spectra and dipole moments indicate the presence of fairly strong O-H ... N hydrogen bonding. The dipole moments and H-1 NMR data in cyclohexane, CCl4, benzene and dioxane show weak association, particularly in cyclohexane and CCl4. The results demonstrate that association leads to the formation of non-polar dimers. In dioxane a complexation with the solvent molecules takes place without the breaking of intramolecular hydrogen bonds.