On racemic and L-malates: a comparison of their crystal structures

Abstract

Abstract The crystal structures of eight different L-malates have been determined and refined from single-crystal X-ray diffraction data. The compounds are the monoclinic (space group P21, Z = 2) L-malates Ca(C4H4O5)·3H2O (a = 6.652(1) Å, b = 8.378(1) Å, c = 8.268(1) Å, β = 112.65(2)°, R = 0.027), Ni(C4H4O5)·3H2O (a = 5.762(1) Å, b = 9.006(2) Å, c = 8.406(1) Å, β = 105.54(1)°, R = 0.024), CuH2 (C4H4O5)2 (a = 9.911(1) Å, b = 5.271(1) Å, c = 11.510(1) Å, β = 109.33(1)°, R = 0.031), CsH(C4H4O5)·H2O (a = 7.439(1) Å, b = 7.481(1) Å, c = 7.852(1) Å, β = 116.67(1)°, R = 0.027) as well as the four isomorphic tetragonal (space group P41212, Z = 4) L-malates MgH2 (C4H4O5)2·4H2O (a = 7.524(1) Å, c = 27.459(2) Å, R = 0.041), MnH2 (C4H4O5)2·4H2O (a = 7.548(1) Å, c = 27.707(2) Å, R = 0.027), CoH2 (C4H4O5)2·4H2O (a = 7.519(1) Å, c = 27.537(2) Å, R = 0.030) and ZnH2 (C4H4O5)2·4H2O (a = 7.533(1) Å, c = 27.360(2) Å, R = 0.029). A comparison of the atomic arrangements of L-malates with their racemic counterparts shows different aspects of symmetry as well as differences in the connectivity of the building units. In addition, for all the compounds, powder diffraction data were collected, analysed and submitted to the powder diffraction file (PDF).