Simulated indentations of aspirin and meloxicam crystals: A molecular-level study of mechanochemistry

MARIA SILVINA MOYANO; MICHAEL FERGUSON; EDUARDO M. BRINGA; CRAWFORD, DEBORAH E.; DEL PÓPOLO, MARIO G.; JORGE KOHANOFF; GARETH A. TRIBELLO; STUART L. JAMES

Conferencia; CEMWOQ 6.5; 2020

While mechanochemical methods continue to show their importance as an alternative synthesis, ourview of the molecular-level events that occur during these processes remains restricted. In this work,indentations between grains of aspirin and meloxicam are modelled through molecular dynamics tosimulate the initial stages of their known mechanochemical co-crystallisation. The effects of smallamounts of solvent, in this case chloroform, are also included in the investigation. Simulations show i)the relatively facile mixing of materials during low-energy indentations in the absence, ii) the formationof a locally amorphous region focused at the contact point between the two grains, iii) plastic-likebehaviour of the materials as a connective neck is formed between the grains upon theirretraction, and that small amounts of solvent molecules have little to no effect at such an early stage ofa reaction, indicating that their role comes into play during the later stages of the mechanochemicalprocess.