Davidson Jonathan A, Jenkins Stephen J, Gorrec Fabrice, Clarke Stuart M
Department of Chemistry, University of Cambridge, Cambridge, UK.
MRC Laboratory of Molecular Biology, Cambridge, UK.
Mol Phys. 2021 Mar 22;119(15-16):e1900940. doi: 10.1080/00268976.2021.1900940. eCollection 2021.
Using a combination of X-ray diffraction and simulation techniques, we are able to identify a crystalline monolayer of 1,3,5-triiodotrifluorobenzene formed on graphite. The monolayer is found to exhibit an incommensurate hexagonal unit cell with a lattice parameter of 9.28(7) Å, exhibiting a trigonal arrangement of iodine atoms not found in the bulk structure. DFT simulations have been performed exhibiting close agreement with the experimental structure. Importantly these simulations can be used to compare the strength of the intermolecular interactions both with and without Van der Waals corrections. Thus it is possible to estimate that halogen bonding consists of approximately half the total interaction energy. This demonstrates that despite the presence of strong directional non-covalent bonding, dispersion interactions account for a very significant proportion of the total energy.
通过结合X射线衍射和模拟技术，我们能够识别出在石墨上形成的1,3,5-三碘三氟苯的晶体单层。发现该单层具有晶格参数为9.28(7) Å的非公度六方晶胞，呈现出在体结构中未发现的碘原子三角排列。进行了密度泛函理论（DFT）模拟，结果与实验结构高度吻合。重要的是，这些模拟可用于比较有无范德华校正时分子间相互作用的强度。因此，可以估计卤素键约占总相互作用能的一半。这表明，尽管存在强方向性非共价键，但色散相互作用在总能量中仍占很大比例。
