Polymorphism in Homochiral Zinc Phosphonates

This paper reports four homochiral zinc phosphonates, α-(S)-[Zn2(pemp)(pempH)Cl] (1), α-(R)-[Zn2(pemp)(pempH)Cl] (2), β-(S)-[Zn2(pemp)(pempH)Cl] (3), and β-(R)-[Zn2(pemp)(pempH)Cl] (4) [pempH2 = (1-phenylethyl)amino]methylphosphonic acid]. Both 1 and 2 are enantiomers, crystallizing in an orthorhombic P212121 space group, while 3 and 4 are polymorphic phases of 1 and 2, respectively, crystallizing in a monoclinic P21 space group. The polymorphism is induced by temperature or additional organic molecules.