(351au) Selective Desolvation of Functional Groups Determines the Crystal Structure during the Process of Crystallization

Crystallization involves self-assembly of solute molecules which results in a crystal with specific structure and morphology. The molecular events in such self-assembly are driven by supersaturation. Understanding of which molecular events lead to the certain outcome of crystallization can significantly improve the efficiency of the crystallization process and reduce the need of post-processing steps. Recently, the dynamics of solvation shell during the process of crystallization were uncovered which were then used to calculate the growth rates. To effectively answer which crystal structure will arise during nucleation, it is necessary to understand the functional group specific desolvation. In this study, molecular dynamics simulations of glutamic acid molecule in water at different supersaturations were performed and the interaction energy phase space arising due to different interactions of different functional groups was explored. Findings of this study suggests that glutamic acid molecules attain a dense phase of energy minima before the formation of crystallization process, similar to the non-classical nucleation mechanism observed for many organic and protein molecules. Further, the groups specific analysis allows mapping the molecular events to the polymorphs of glutamic acid. At high supersaturation, the energy minima in the phase space matches with the metastable polymorph of the crystal structure suggesting the asymmetric distribution of water around different functional groups determines the crystal structure.