Polymorphism and structural diversities of LiClO4–β-alanine ionic co-crystals

Three novel ionic co-crystals built from lithium perchlorate and β-alanine (LiClO₄·βAla, LiClO₄·2βAla-I, LiClO₄·2βAla-II) are discussed in terms of structural differences. A detailed description of the polymorphic phase transition is given.

Mechanochemical preparation of molecular and ionic co-crystals of the hormone melatonin

Molecular and ionic co-crystals of melatonin with piperazine, DABCO and CaCl₂ were obtained via kneading with ethanol: the solubility of melatonin in H₂O increases by an order of magnitude when combined with CaCl₂.

Ionic Co-Crystal Formation as a Path Towards Chiral Resolution in the Solid State

The preparation and characterization of a whole family of hydrated ionic co-crystals formed by both enantiopure l-proline and racemic dl-proline with LiX (X=Cl, Br, I) are reported. The chiral preference of the lithium cation for homochiral coordination, both in the formation of crystalline conglomerates (with Cl and Br) and racemates (with Cl and I), in which molecules of opposite chirality are confined to distinct crystal layers, is discussed. Dehydration processes for all hydrated crystals have also been investigated.

Solid-state chiral resolution mediated by stoichiometry: crystallizing etiracetam with ZnCl2

Co-crystallization of racemic etiracetam with ZnCl₂ results in a racemic compound or a conglomerate, depending on the amount of ZnCl₂; the unprecedented behaviour was investigated through a racetam/ZnCl₂/solvent phase diagram.

Organic–inorganic ionic co-crystals: a new class of multipurpose compounds

Reacting molecular organic solids with inorganic salts gives access to novel properties via ionic co-crystal formation.