1-[Morpholino(phenyl)methyl]-2-naphthol

There are two independent molecules in the asymmetric unit of the title compound, C21H21NO2, which was synthesized by the one-pot reaction of 2-naphthol, morpholine and benzaldehyde. The dihedral angles between the naphthalene ring systems and the benzene rings are 84.03 (7) and 75.76 (8)° in the two molecules and an intramolecular O—H⋯N hydrogen bond occurs in each independent molecule.

(morpholino(phenyl)methyl)naphthalen-2-ol, the dielectric constant as a function of temperature goes smoothly, and there is no dielectric anomaly observed (dielectric constant equaling to 3.6 to 5.3, measured temperature ranges: 80 K to 430 K).
In the molecule of the title compound ( Fig. 1), the bond lengths and angles are within their normal ranges. There are two molecules which have the same relative conformation in one asymmetric unit. The dihedral angle between the naphthylene ring A (C1-C10) and benzene ring B (C11-C16) is A/B =84.05 °. The dihedral angle between the naphthylene ring C (C18-C27) and benzene ring D (C28-C33) is C/D =75.80 °. The morpholine ring in two molecules both adopt chair conformation. The two molecules are both stabilized by strong intramolecular O-H···N hydrogen bonding (Table 1). The intermolecular attractions are only on the order of Van der Waals forces.

Experimental
Benzaldehyde (1.06 g, 0.010 mol) was added to 2-naphthol (1.44 g, 0.010 mol) without solvent. Then morpholine (0.87 g, 0.010 mol) was added dropwise with cooling to 0°C to the above mixture. The temperature was raised to 120°C in one hour gradually and the mixture was stirred at this temperature for 10 hours. Then 15 ml of ethanol 95% was added, after heating under reflux for 30 min, the precipitate was filtered off and washed 3 times with a small amount of ethanol 95% to give the title compound. Single crystals suitable for X-ray diffraction analysis were obtained from slow evaporation of chloroform solution.

Refinement
All H atoms were calculated geometrically, with C-H = 0.93-0.97 Å, O-H= 0.82 Å, and refined as riding with Uiso(H)= 1.2Ueq(C) or 1.2Ueq(O) for hydroxy hydrogen atoms. Fig. 1. The molecular structure of the title compound, showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.