Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA.
Molecules. 2021 Oct 22;26(21):6394. doi: 10.3390/molecules26216394.
Molecules of the type XYT = Ch (T = C, Si, Ge; Ch = S, Se; X,Y = H, CH, Cl, Br, I) contain a σ-hole along the T = Ch bond extension. This hole can engage with the N lone pair of NCH and NCCH so as to form a chalcogen bond. In the case of T = C, these bonds are rather weak, less than 3 kcal/mol, and are slightly weakened in acetone or water. They owe their stability to attractive electrostatic energy, supplemented by dispersion, and a much smaller polarization term. Immersion in solvent reverses the electrostatic interaction to repulsive, while amplifying the polarization energy. The σ-holes are smaller for T = Si and Ge, even negative in many cases. These Lewis acids can nonetheless engage in a weak chalcogen bond. This bond owes its stability to dispersion in the gas phase, but it is polarization that dominates in solution.
类型为 XY T = Ch（T = C、Si、Ge；Ch = S、Se；X、Y = H、CH、Cl、Br、I）的分子沿 T = Ch 键伸展方向含有 σ 空穴。该空穴可与 NCH 和 NCCH 的 N 孤对电子结合，从而形成硫属键。在 T = C 的情况下，这些键非常弱，小于 3 kcal/mol，在丙酮或水中会稍微减弱。它们的稳定性归因于吸引力静电能，辅以色散，以及较小的极化项。溶剂的浸入会使静电相互作用从吸引变为排斥，同时放大极化能。对于 T = Si 和 Ge，σ 空穴更小，在许多情况下甚至为负。尽管如此，这些路易斯酸仍能形成较弱的硫属键。这种键的稳定性归因于气相中的色散，但在溶液中起主导作用的是极化。
