Crystal structure and conformation of 2-{2 '-aminobenzyl)iminoethyl}5-methoxyphenol

The Schiff base, 2-{(2 ' -aminobenzyl)iminoethyl}-5-methoxyphenol,1,2-C6H4[ NH2-2 ']-CH2N=CHC6H3(OMe-5)OH (I), has been prepared by the reaction of 2-a mino-1-benzylamine and 2-hydroxy-4-methoxyacetophenone in methanol. The mol ecular structure has been confirmed by single crystal X-ray crystallography (triclinic, space group P (1) over bar a = 7.201(2), b = 9.802(2), c = 9.9 93(2) Angstrom, alpha = 83.09(2), beta = 73.49(2), gamma = 84.09(2)degrees R = 0.0415 for 2611 independent reflections). The H-1 and C-13 NMR spectra in CDCl3 solution indicate the formation of some other minor conformations or dissociation in solution. The title compound is not planar. Intramolecul ar hydrogen bonding occurs between O(1) and N(1) atoms [2.528(2) Angstrom], the hydrogen atom essentially being bonded to the nitrogen atom. Minimum e nergy conformations from AM 1 were calculated as a function of four torsion angles. The optimized geometry of the molecular structure corresponding to the non-planar conformation is the most stable conformation in all calcula tions. The results strongly indicate that the minimum energy conformation i s primarily determined by non-bonded hydrogen-hydrogen repulsions.