(R)-Methyl {[(2-carboxybicyclo[2.2.2]octan-1-yl)ammonio]methyl}phosphonate dichloromethane 0.25-solvate

Abstract

The carboxylic acid molecule of the title compound, C11H20NO5P·0.25CH2Cl2, exists as a zwitterion with the H atom of the phosphonate group being transferred to the imine N atom. In the asymmetric unit, there are two crystallographically independent acid molecules adopting the same absolute configuration and differing slightly in their geometrical parameters. In each molecule, the imino and carboxyl groups are connected via an intramolecular N—H...O hydrogen bond. Intermolecular O—H...O and N—H...O hydrogen bonds induce the formation of layers parallel to the ab plane. The dichloromethane solvent molecule, with a site occupancy of 0.5, is located between the layers.