The Stoichiometry, Structure and Possible Formation of Crystalline Diastereomeric Salts

• Main Authors: Dorottya Fruzsina Bánhegyi, Emese Pálovics
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Symmetry
• Subjects: predictable resolution; supramolecular associations; helical structure; eutectic composition
• Online Access: https://www.mdpi.com/2073-8994/13/4/667

Knowing the eutectic composition of the binary melting point phase diagrams of the diastereomeric salts formed during the given resolution, the achievable F (F = ee_Dia*Y) value can be calculated. The same value can also be calculated and predicted by knowing the eutectic compositions of the binary melting point phase diagrams of enantiomeric mixtures of the racemic compound or the resolving agent. An explanation was sought as to why and how the crystalline precipitated diastereomeric salt—formed in the solution between a racemic compound and the corresponding resolving agent—may be formed. According to our idea, the self-disproportionation of enantiomers (SDE) has a decisive role when the enantiomers form two nonequal ratios of conformers in solution. The self-organized enantiomers form supramolecular associations having M and P helicity, and double helices are formed. Between these double spirals, with the formation of new double spirals, a dynamic equilibrium is achieved and the salt crystallizes. During this process between acids and bases, chelate structures may also be formed. Acids appear to have a crucial impact on these structures. It is assumed that the behavior of each chiral molecule is determined by its own code. This code validates the combined effect of constituent atoms, bonds, spatial structure, charge distribution, flexibility and complementarity.