Haberhauer Gebhard, Gleiter Rolf
Institut für Organische Chemie, Universität Duisburg-Essen, Universitätsstr. 7, 45117, Essen, Germany.
Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
Angew Chem Int Ed Engl. 2020 Nov 16;59(47):21236-21243. doi: 10.1002/anie.202010309. Epub 2020 Sep 7.
Chalcogen bonds are σ hole interactions and have been used in recent years as an alternative to hydrogen bonds. In general, the electrostatic potential at the chalcogen atom and orbital delocalization effects are made responsible for the orientation of the chalcogen bond. Here, we were able to show by means of SAPT calculations that neither the induction (orbital delocalization effects) nor the electrostatic term is causing the spatial orientation of strong chalcogen bonds in tellurium-containing aromatics. Instead, steric interactions (Pauli repulsion) are responsible for the orientation. Against chemical intuition the dispersion energies of the examined tellurium-containing aromatics are far less important for the net attractive forces compared to the energies in the corresponding sulfur and selenium compounds. Our results underline the importance of often overlooked steric interactions (Pauli repulsion) in conformational control of σ hole interactions.
硫族元素键是σ空穴相互作用，近年来已被用作氢键的替代物。一般来说，硫族元素原子处的静电势和轨道离域效应决定了硫族元素键的取向。在此，我们通过对称性适配微扰理论（SAPT）计算表明，在含碲芳烃中，无论是诱导作用（轨道离域效应）还是静电项都不会导致强硫族元素键的空间取向。相反，空间相互作用（泡利排斥）决定了其取向。与化学直觉相反，与相应的硫和硒化合物中的能量相比，所研究的含碲芳烃的色散能对净吸引力的影响要小得多。我们的结果强调了在σ空穴相互作用的构象控制中常常被忽视的空间相互作用（泡利排斥）的重要性。
