STRUCTURE OF 3,5-PYRAZOLEDIMETHANOL - AN X-RAY AND C-13 SOLID-STATE NMR-STUDY

C5H8N2O2, M(r) = 128.1, monoclinic, C2/c, a = 12.9884 (5), b = 4.6517 (1), c = 20.7870 (11) angstrom, beta = 102.436 (3)-degrees, V = 1226.44 (9) angstrom 3, Z = 8, D(x) = 1.388 Mg m-3, lambda(Cu K-alpha) = 1.5418 angstrom, mu = 0.877 mm-1, F(000) = 544, T = 293 K, R = 0.051 for 900 observed reflections The hydroxyl group are situated almost perpendicular to the pyrazole ring. The crystal structure is stabilized by strong linear N-H...N, N-H...O, O-H...N and O-H...O hydrogen bonds. Although two identical tautomers are present in the crystal, no dynamic behaviour was observed by NMR (C-13 CP/MAS technique) proving that the disorder is static.