Department of Chemical System Engineering, School of Engineering, The University of Tokyo 7-3-1, Tokyo 113-8656, Japan.
Phys Chem Chem Phys. 2019 Sep 18;21(36):19969-19986. doi: 10.1039/c9cp03783g.
Several recent studies have shown that chalcogen bonds originate from the σ-holes localized on the electron-deficient surface of the Group 16 atoms (sulfur, selenium and tellurium) in molecules; however, the oxygen atom in molecules does not appear to form such a bond. In this study, we have considered oxygen difluoride (OF2) as a prototypical Lewis acid, and 11 Lewis bases as partner interacting species (CH3F, CH3Cl, CH3Br, H2CO, HFCO, HF, SO, CH3CN, PN, HSCN and HCN). Their complexes are examined using DFT-M06-2X and ab initio first-principles calculations at the MP2 level of theory, in conjunction with Dunning's all-electron correlated basis set aug-cc-pVTZ. The results that emerge from the equilibrium geometries, molecular electrostatic surface potential, second order natural bond orbital, quantum theory of atoms in molecules, reduced density gradient and independent gradient model noncovalent analyses tools, as well as from binding energy calculations, demonstrate that oxygen is indeed capable of forming a chalcogen bond. We show that the σ-holes on O along the F-O bond extensions in OF2 are positive, and can readily participate in chalcogen bonding (and other secondary interactions) with Lewis bases, thus providing stability to the geometries of all the 12 binary complexes examined. Finally, we demonstrate that without invoking charge density topologies the often used electrostatic surface potential model is certainly inadequate for the exploration of the noncovalent topology of bonding interactions in the majority of the dimers examined.
几项最近的研究表明，硫属键源于分子中缺电子的第 16 族原子（硫、硒和碲）表面上的 σ 空穴；然而，分子中的氧原子似乎没有形成这样的键。在这项研究中，我们将二氟化氧（OF2）视为典型的路易斯酸，并将 11 种路易斯碱作为相互作用的伙伴相互作用物种（CH3F、CH3Cl、CH3Br、H2CO、HFCO、HF、SO、CH3CN、PN、HSCN 和 HCN）。使用 DFT-M06-2X 和 MP2 水平的从头算第一性原理计算，结合 Dunning 的全电子相关基组 aug-cc-pVTZ，对它们的配合物进行了研究。从平衡几何形状、分子静电表面电位、二阶自然键轨道、分子中的原子量子理论、密度梯度缩减和独立梯度模型非共价分析工具以及结合能计算得出的结果表明，氧确实能够形成硫属键。我们表明，OF2 中沿 F-O 键延伸的 O 上的 σ 空穴为正，并且可以与路易斯碱容易地参与硫属键（和其他次级相互作用），从而为所有 12 个二元配合物的几何形状提供稳定性。最后，我们证明，如果不考虑电荷密度拓扑，常用的静电表面电位模型肯定不足以探索大多数所研究的二聚体中的非共价键拓扑结构。
