Crystal Structures of D-(+)- and meso-Hydrobenzoin. Absolute Direction of the Dipole Moment of D- and L-Hydrobenzoin in the Crystal and Correlation with Crystal Morphology, Pyroelectric Effect, and Absolute Configuration

Article abstract of DOI:10.1021/ja00227a034

Polar crystals of racemic hydrobenzoin have been shown to react to give benzaldehyde at different rates along the two directions of the polar axis when suspended in aqueous potassium periodate.The Kundt-Buerker pyroelectric test shows well-developed electrical polarity.A crystal structure determination permits correlation of these phenomena with the internal structure of the crystal.The crystals are monoclinic, a = 5.8372(9) Angstroem, b = 7.904(1) Angstroem, c = 12.405(2) Angstroem, β = 93.04(1) degree, the space group is P2₁, and the structure has been refined to an R factor of 0.033 on 1154 nonzero reflections.The structure of meso-hydrobenzoin shows the molecules to exist in the centrosymmetric anti conformation.Crystals are monoclinic, a = 12.542(2) Angstroem, b = 5.084(1) Angstroem, c = 9.305(1) Angstroem, β = 106.67(2) degree, the space group is P2₁/c.Refinement resulted in R = 0.045 based on 748 nonzero reflections.