To understand the deformation mechanism of molecular crystals under mechanical forces will accelerate the molecular design and preparation of deformable crystals. Herein, the relationship between structural halogenation and molecular-level stacking, micro/nanoscale surface morphology, and macroscopic mechanical properties are investigated. Elastic crystals of halo-pyrimidinyl carbazoles (CzM-Cl, CzM-Br and CzM-I) with lamellar structure and brittle crystal (CzM-F) were quantitatively analyzed by crystal energy framework (CEF) providing the inter/intralayer interaction energy (Inter/Intra-IE). It is revealed that the elastic crystals bend under external force as a result from stronger Intra-IE to prevent cleavage and weaker Inter-IE for the short-range movement of molecules on the slip plane. This research will provide an insight for the molecular design of flexible crystals and facilitate the development of next-generation smart crystal materials.

了解分子晶体在机械力作用下的变形机制将加速可变形晶体的分子设计和制备。在此，研究了结构卤化与分子级堆积、微/纳米尺度表面形貌和宏观力学性能之间的关系。卤代嘧啶基弹性晶体通过提供层间/层内相互作用能（Inter/Intra-IE）的晶体能量框架（CEF）对具有层状结构和脆性晶体（CzM-F）的咔唑（CzM-Cl、CzM-Br和CzM-I）进行定量分析。结果表明，弹性晶体在外力作用下弯曲是由于较强的Intra-IE以防止解理和较弱的Inter-IE以防止分子在滑移面上的短程运动。这项研究将为柔性晶体的分子设计提供见解，并促进下一代智能晶体材料的开发。