Madan Kumar S
DST-PURSE Lab, Mangalore University, India.
Heliyon. 2019 Feb 5;5(2):e01209. doi: 10.1016/j.heliyon.2019.e01209. eCollection 2019 Feb.
The tetramorph crystals of 4,4-dimethylbenzophenone () were obtained using slow-evaporation crystallization method and the structure is elucidated using single crystal X-ray diffraction technique. crystallizes in the orthorhombic crystal system (space group ) with cell parameters = 14.6986 (11) Å, = 6.1323 (4) Å, = 26.2730 (18) Å, = 2368.2 (3) Å and = 8. In the crystal structure, intermolecular interaction of the type C---Hπ stabilizes the crystal packing. This polymorph is the fourth candidate of its kind and second candidate in the orthorhombic crystal system. The structural comparisons and crystal packing of tetramorphs (, , and ) are analyzed using molecular structures, Hirshfeld surfaces, enrichment ratios () and energy frameworks. The conformational differences are observed in all the tetramorphs and the intercontacts H H and C H contributes around 85 % to the Hirshfeld surfaces. The ratio provides evidence of H H, C H and O H intercontacts having high propensity to form contacts in the crystal packing. The average energy (dimer formation) for each polymorph is calculated from energy framework analysis. The systematic comparison of crystal packing in tetramorphs through 3D-topology is visualized. In the energy-frameworks of the crystal packing, dispersion energy dominates over the electrostatic energy. Overall, the molecular packings of the four polymorphic structures are different.
采用缓慢蒸发结晶法获得了4,4-二甲基二苯甲酮（）的四变体晶体，并使用单晶X射线衍射技术阐明了其结构。该晶体属于正交晶系（空间群），晶胞参数为 = 14.6986 (11) Å， = 6.1323 (4) Å， = 26.2730 (18) Å， = 2368.2 (3) Å， = 8。在晶体结构中，C---Hπ型分子间相互作用稳定了晶体堆积。这种多晶型是同类中的第四个候选物，也是正交晶系中的第二个候选物。使用分子结构、Hirshfeld表面、富集率（）和能量框架对四变体（、、和）的结构比较和晶体堆积进行了分析。在所有四变体中都观察到了构象差异，H H和C H的相互接触对Hirshfeld表面的贡献约为85%。 比率提供了H H、C H和O H相互接触在晶体堆积中具有高形成接触倾向的证据。通过能量框架分析计算了每种多晶型的平均能量（二聚体形成）。通过三维拓扑对四变体中晶体堆积的系统比较进行了可视化。在晶体堆积的能量框架中，色散能占主导地位，超过静电能。总体而言，四种多晶型结构的分子堆积不同。
