Conformation and structure of 3-methoxyphenyl-salicylaldimine

3-methoxyphenyl-salicylaldimine (C14H13NO2) was studied by X-ray analysis a nd AM1 molecular orbital methods. It crystallises in the monoclinic space g roup P2(1)/c with n = 20.486(4) Angstrom, b = 4.7935(8) Angstrom Angstrom, c = 12.310(5) Angstrom, beta = 107.43(2)degrees, V = 1153.3(6) Angstrom(3), Z = 4, D-0 = 1.309 g cm(-3), Z = 4, and mu(MoKalpha) = 0.088 mm(-1). The s tructure was solved by direct methods and refined to R = 0.033 for 1635 ref lections [I < 2((I)]. The title molecule was nearly planar. There was a str ong intramolecular hydrogen bond of distance 2,598(2) Angstrom between the hydroxyl oxygen atom and imine nitrogen atom, the hydrogen atom essentially being bonded to the oxygen atom. Minimum energy conformations from AM1 wer e calculated as a function of the three torsion angles theta(1)(C8-N1-C7-C6 ), theta(2)(N1-C7-C6-C5), and theta(3)(C9-C8-N1-C7) varied every 10 degrees . The theoretical calculations were carried out to compare with experimenta l results of the molecular conformations. The optimized geometry of the cry stal structure corresponding to a non-planar conformation is the most stabl e conformation in all theoretical calculations. (C) 1999 Elsevier Science B .V. All rights reserved.