Application of Wallach's rule in a comparison of the X-ray crystal structures of the racemate and the (S) enantiomer of (1-hydroxy-3-phenyl-2-propenyl) dimethylphosphonate

The crystal structures of the racemate and the (S) enantiomer of (1-ydroxy-3-phenyl-2-propenyl) dimethylphosphonate, C11H15O4P, were determined by X-ray diffraction. The crystal density of the racemate was found to be 6.2% greater than the crystal density of the (S) enantiomer. In both crystal structures the molecules form chains by hydrogen bonding between the OH of one molecule and the P double bond O of another. Observed differences in atomic displacement between the two structures are discussed in view of the C-H ... O interactions.