Crystal Morphology\nPrediction of 2,6-Diamino-3,5-Dinitropyrazine-1-Oxide\n(LLM-105) Using a Spiral Growth Model and a Refined OPLS-AA Force\nField

2,6-Diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is\nrepresentative\nof low-sensitivity and high-energy compounds with a potential for\nwide application, and morphology control is crucial to guarantee the\napplication. However, due to insufficient accuracy of general force\nfields and no kinetic factor considered in common models, it can hardly\nmake accurate morphology predictions, and thus, the control is uncontrollable.\nThis work refines an OPLS-AA force field esspecially for LLM-105 and\napplies it to morphology prediction with a spiral growth model in\nthree solvents of dimethyl sulfoxide, <i>N</i>-methyl pyrrolidone,\nand dimethylformamide. By comparing aspect ratios and predominant\nface areas of the predictions and experiments, we confirm the advantage\nof our method over other models and force fields. Intermolecular interaction\nanalyses show the dominance of π–π stacking, followed\nby hydrogen bonding. Due to the strong molecular bond chains dominated\nby π–π stacking along the [100] edge of the (011)\ncrystal surface, the rod-like growth occurs thereon in all three solvents.\nThis work is rooted in the morphology control of LLM-105 and can also\nbe referred to for other organic molecular crystals.