info:eu-repo/semantics/article
Insights into mechanochemical reactions at the molecular level: Simulated indentations of aspirin and meloxicam crystals
Fecha
2019-01Registro en:
Ferguson, Michael; Moyano, María Silvina; Tribello, Gareth A.; Crawford, Deborah E.; Bringa, Eduardo Marcial; et al.; Insights into mechanochemical reactions at the molecular level: Simulated indentations of aspirin and meloxicam crystals; Royal Society of Chemistry; Chemical Science; 10; 10; 1-2019; 2924-2929
2041-6520
CONICET Digital
CONICET
Autor
Ferguson, Michael
Moyano, María Silvina
Tribello, Gareth A.
Crawford, Deborah E.
Bringa, Eduardo Marcial
James, Stuart L.
Kohanoff, Jorge
del Popolo, Mario Gabriel
Resumen
Although solvent-free mechanochemical synthesis continues to gain ever greater importance, the molecular scale processes that occur during such reactions remain largely uncharacterised. Here, we apply computational modelling to indentations between particles of crystals of aspirin and meloxicam under a variety of conditions to mimic the early stages of their mechanochemical cocrystallisation reaction. The study also extends to the effects of the presence of small amounts of solvent. It is found that, despite the solid crystalline nature of the reactants and the presence of little or no solvent, mixing occurs readily at the molecular level even during relatively low-energy collisions. When indented crystals are subsequently drawn apart, a connective neck formed by a mixture of the reactant molecules is observed, suggesting plastic-like behaviour of the reacting materials. Overall the work reveals some striking new insights including (i) relatively facile mixing of crystals under solvent-free conditions, (ii) no appreciable local temperature increases, (iii) localised amorphisation at the contact region and neck of the reacting crystals, and (iv) small amounts of solvent have relatively little effect during this early stage of the reaction, suggesting that their accelerating effect on the reaction may be exerted at later stages.