Probing the role of energetics in the mechanosynthesis of multicomponent crystal forms Sharmarke Mohamed Khalifa University, United Arab Emirates There have been numerous reports of mechanochemically prepared multicomponent crystals to date. Whilst mechanical force and local heating inside the milling media are important factors that affect chemical or physical transformations, the exact mechanism for the crystallization of multicomponent crystals inside a ball- mill remain largely elusive. This is despite recent insights gained using in-situ methods for monitoring the ball-milling process using spectroscopic or diffraction methods. In this lecture, we ask whether ball-milling is biased towards thermodynamic products of crystallization? The answer to this question is fundamental for the industrial application of mechanochemistry as we know that many active ingredients can exist in a range of polymorphic and variable stoichiometry phases. Here, we focus on the use of ball-milling for the crystallization of three energetically diverse sets of multicomponent systems, namely eutectics [1], solvates and higher-order cocrystals [2]. We review the energetics of these processes using insights gained from computational methods, including crystal structure prediction, DFT and Monte Carlo methods. Our work probes the energetic cost for the crystallization of these multicomponent systems and our results suggest that the outcome of ball-milling (thermodynamic vs. kinetic products) is system dependent and cannot easily be generalized. Nevertheless, in all cases, our computational results were consistent with the experimental results, suggesting the value of computational methods in mechanochemistry experiments. References 1. S. Mohamed* et al, Cryst. Growth Des. 2021, 21, 7, 4151–4161. 2. S. Mohamed*, F. García* et al, Angew. Chem. Int. Ed. 2021, 60, 17481.
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