(R)-Methyl {[(2-carb-oxy-bicyclo-[2.2.2]octan-1-yl)-ammonio]-methyl}-phos-phon-ate dichloro-methane 0.25-solvate

Abstract

The carb-oxy-lic acid mol-ecule of the title compound, C(11)H(20)NO(5)P·0.25CH(2)Cl(2), exists as a zwitterion with the H atom of the phospho-nate group being transferred to the imine N atom. In the asymmetric unit, there are two crystallographically independent acid mol-ecules adopting the same absolute configuration and differing slightly in their geometrical parameters. In each mol-ecule, the imino and carboxyl groups are connected via an intra-molecular N-H⋯O hydrogen bond. Inter-molecular O-H⋯O and N-H⋯O hydrogen bonds induce the formation of layers parallel to the ab plane. The dichloro-methane solvent mol-ecule, with a site occupancy of 0.5, is located between the layers.

Fig. 1.

The asymmetric unit of title compound with the atom numbering scheme showing 50% probability displacement ellipsoids. H atoms have been omitted for clarity.

Fig. 2.

The packing arrangement of the molecules in the unit cell, showing the hydrogen-bonding interactions as dashed lines. [symmetry codes: (i) 1 - x, y - 1/2, 1/2 - z; (ii) 1/2 - x, 1 - y, 1/2 + z; (iii) 1/2 + x, 1/2 - y, 1 - z; (iv) 1/2 + x, 1.5 - y, 1 - z;

Fig. 3.

NMR numbering scheme.