Formation of molecular complexes and subsequent heterolytic halogen‐halogen bond splitting upon reactions of molecular Cl2 with nitrogen‐containing Lewis bases (LB) are computationally studied at M06‐2X/def2‐TZVPD and for selected compounds at CCSD(T)/aug‐cc‐pvtz//CCSD/aug‐cc‐pvtz levels of theory. Obtained results are compared with data for ICl and I2 molecules. Reaction pathways indicate, that in case of Cl2∙LB complexes the activation energies for the heterolytic Cl‐Cl bond splitting are lower than the activation energies of the homolytic splitting of Cl2 molecule into chlorine radicals. The heterolytic halogen splitting of molecular complexes of X2∙Py with formation of [XPy2]+… contact ion pairs in the gas phase is slightly endothermic in case of Cl2 and I2, but slightly exothermic in the case of ICl. Formation of {[ClPy2]+…}2 dimers makes the overall process exothermic. Taking into account that polar solvents favor ionic species, generation of donor‐stabilized Cl+ in the presence of the Lewis bases is expected to be favorable. Thus, in polar solvents the oxidation pathway via donor‐stabilized Cl+ species is viable alternative to the homolytic Cl‐Cl bond breaking.

中文翻译：

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与路易斯碱反应时分子氯容易发生杂解键断裂：与 ICl 和 I2 的比较


在 M06-2X/def2-TZVPD 上对分子配合物的形成以及随后的分子 Cl2 与含氮路易斯碱 (LB) 反应时的异解卤素-卤键断裂进行了计算研究，并在 CCSD(T)/aug-cc 上对选定的化合物进行了计算研究‐pvtz//CCSD/aug‐cc‐pvtz 理论水平。将获得的结果与ICl和I2分子的数据进行比较。反应路径表明，对于 Cl2∙LB 配合物，Cl-Cl 键杂裂的活化能低于 Cl2 分子均裂分裂成氯自由基的活化能。 X2∙Py 分子配合物的异解卤素分裂并在气相中形成 [XPy2]+… 接触离子对，对于 Cl2 和 I2 来说是轻微吸热的，但对于 ICl 来说是轻微放热的。 {[ClPy2]+…}2 二聚体的形成使整个过程放热。考虑到极性溶剂有利于离子物种，在路易斯碱存在下预计有利于生成供体稳定的 Cl+。因此，在极性溶剂中，通过供体稳定的 Cl+ 物质的氧化途径是均裂 Cl-Cl 键断裂的可行替代方案。