Cobalt complex of cinchonine: intermolecular interactions in two crystalline modifications.

Abstract

Two crystalline modifications of cinchonine cobalt complex, C19H23Cl3CoN2O, were obtained from mixture of saturated alcohol solutions of CoCl3 x 6H2O and cinchonine. The X-ray structure analysis revealed that the asymmetric unit of one modification, CoCn1, contains only zwitterionic molecules of the complex. In the asymmetric unit of the other, CoCn2, there are two molecules of the title compound and two molecules of ethanol. The influence of the absolute configuration, the CoCl3 coordination with quinoline, and the presence of alcohol molecules on the studied structures was established by comparison of the crystal and molecular structures of both cobalt complexes with the analogous quinine complex and zinc complex of cinchonine. The interactions that dominate in the packing of the molecules in both structures are intermolecular hydrogen bonds. They form characteristic ring systems, depending on the presence of the alcohol molecules. The ring features are also related to the absolute configuration of the alkaloid.