Balmohammadi Yaser, Malaspina Lorraine A, Nakamura Yuiga, Cametti Georgia, Andrzejewski Michał, Siczek Milosz, Grabowsky Simon
Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012, Bern, Switzerland.
Japan Synchrotron Radiation Research Institute (JASRI), Sayo-Cho, Hyogo, 679-5198, Japan.
Sci Rep. 2025 Apr 29;15(1):15045. doi: 10.1038/s41598-025-95269-3.
2-Dimethylsulfuranylidene-l,3-indanedione (YLID) is the most common crystal structure in the world not because of its chemical or physical properties, but because of its use as a test crystal for commercial diffractometers by nearly all vendors for more than 50 years. We will use it as an example here to showcase how the application of modern quantum-crystallographic refinement techniques and new experiments can unravel a so-far hidden story, which puts the emphasis back on the interesting chemical and physical properties of this crystal structure. We present a new chiral form of orthorhombic YLID (the left-handed LS form) and describe the complicated relationship between helical crystal packing and molecular planar chirality. We investigate polymorphs of YLID with twisted and planar molecular configuration as a function of temperature (100 to 292 K) and external pressure (0 to 4 GPa). However, finally only chemical pressure, namely the insertion of water into the crystal structure, can transform the twisted into the planar structure. A combination of quantum crystallography and repeated measurements of the orthorhombic test crystal gives access to an estimate of reproducibility and reliability of refining both anomalous dispersion and Flack parameters. It appears that the chemical environment of covalently bonded atoms has an influence on the anomalous dispersion parameters.
2-二甲基硫亚基-1,3-茚二酮（叶立德）并非因其化学或物理性质，而是因其在超过50年的时间里几乎被所有供应商用作商业衍射仪的测试晶体，从而成为世界上最常见的晶体结构。我们在此将以它为例，展示现代量子晶体学精修技术的应用和新实验如何能够揭开一个迄今为止隐藏的故事，这个故事将重点重新放回了这种晶体结构有趣的化学和物理性质上。我们展示了正交晶系叶立德的一种新的手性形式（左旋LS形式），并描述了螺旋晶体堆积与分子平面手性之间的复杂关系。我们研究了具有扭曲和平面分子构型的叶立德多晶型物随温度（100至292K）和外部压力（0至4GPa）的变化情况。然而，最终只有化学压力，即向晶体结构中插入水，才能将扭曲结构转变为平面结构。量子晶体学与正交测试晶体的重复测量相结合，能够对反常色散和弗拉克参数精修的再现性和可靠性进行估计。似乎共价键合原子的化学环境对反常色散参数有影响。
