Stereochemical studies on nucleation, growth and reactivity of organic crystals

In this lecture we present a stereochemical approach to crystal growth and dissolution and processes related to topochemical polymerizations in the solid phase. Understanding of such processes should take into consideration the packing arrangements of the crystals involved, the texture and kinetics of growth of the faces that delineate these crystals as well as the nature of the solvent where the crystals are grown or reacted and the structures of possible supramolecular architecures formed in the solution by the molecules undergoing crystallization. This stereochemical methodology is represented by the following three examples: (i) The role played by the addition of methanol or ethanol in the precipitation of the metastable β-form of glycine, (ii) The resolution of several α-amino acids salts that crystallize in enantiomorphous space groups, however, are composed form alternating lamellae of opposite handedness, and (iii) Polymerization reaction in crystals where the short chains formed in the course of the reaction self-assemble and induce the formation of isotactic polymers.