THE STRUCTURE AND TAUTOMERIC PROPERTIES OF 2-(3-PYRIDYLMETHYLIMINOMETHYL)PHENOL

The structure and properties of 2-(3-pyridylmethyliminomethyl)phenol have been determined by X-ray crystallography, NMR, UV and IR spectroscopy and compared with the characteristics of the Schiff bases derived from salicylaldehyde and aminopyridines. Crystal data: C13H12N2O, M(r) = 212.250, monoclinic, space group P2(1)/n, a = 10.49(1) angstrom, b = 9.002(4) angstrom, c = 12.42(1) angstrom, beta = 109.10(4)-degrees, V = 1109(2) angstrom, Z = 4, D(x) = 1.271 g cm-3, MoKalpha (lambda = 0.71073 angstrom), mu = 0.8 cm-1, F(000) = 448, T = 297 K, R = 0.049, R(W) = 0.053 for 886 reflections with I > 2sigma(I). Bond distances and bond angles are similar to those of 2-(pyridyliminomethyl)phenols. In the title molecule the dihedral angle between the pyridine and benzene least-squares planes is 89.9(2)-degrees. There is an intramolecular O1-H ... N1 hydrogen bond of 2.572(5) angstrom. In solutions of polar solvents tautomeric interconversion of the Schiff base into the ketoamine is observed. Corresponding equilibrium constants are estimated in a variety of solvents on the basis of UV spectral data.