The effect of crystal-solvent interaction on crystal growth and morphology

Abstract

Diacetone diperoxide (DADP)/1,3,5-tribromo-2,4,6-trinitrobenzen (TBTNB) and diacetone diperoxide (DADP)/1,3,5-trichloro-2,4,6-trinitrobenzen (TCTNB) cocrystals were selected to reveal the effect of interaction at solvent-crystal interface on crystal growth and morphology, and analyze the interaction at the interface by molecular electrostatic potentials (ESP), mass density distribution and radial distribution function (RDF). It can be found that in DADP/TBTNB-acetonitrile interface model, the interaction at (0 2 0) face is the greatest and presents as repulsive interaction, so the growth rate of (0 2 0) face is the largest and the (0 2 0) face is the smallest. Conversely, the least and attractive interaction at interface tends to make (1 1 −1) to be the largest. These deductions are in accordance with the simulation of DADP/TBTNB cocrystal morphology in acetonitrile, and similar conclusion also can be obtained from the growth of DADP/TBTNB cocrystal in cyclohexanone. These are related to cavities of cocrystal face, which affect the distribution and orientation of solvent molecules. It can be reasoned out that the quantity of cavities on crystal face and the electrophilicity or nucleophilicity of solvent molecules may inhibit or facilitate the growth of crystal face.