X-ray and neutron diffraction studies of the crystal and molecular structure of the predominant monocarboxylic acid obtained by mild acid hydrolysis of cyanocobalamin. Part I. X-ray diffraction studies of air dried crystals

Abstract

The crystal stmcture of air-dried crystals of the O-monocarboxyic acid of cyanocobalamin, E2, has been solved by x-ray analysis. The lattice constants are n = 14.51 A b = 17-09 A, e = 16-35 A. p = 103"; space group P2,. Phare angles were derived from observations on a n e a u s dispersion effects for 2567 of the measured 2875 pairs of reflections, hkl and hkl, and usnf in the solution of the structure The intensities of reflexions were eye estimated from Weissenberg photographs. The molecular arrangement is very dierent from that of other cyanowbalaminr; the corrin rings of neighbouring molecules are at ca 90" to one another. It was not wssihle to r e c o- d e t h e oneacid -m ouo amone the amides & with certainty.