BDE261: A Comprehensive Set of High-Level Theoretical Bond Dissociation Enthalpies

We have used the high-level W1w protocol to compile a comprehensive collection of 261 bond dissociation enthalpies (BDEs) for bonds connecting hydrogen, first-row and second-row p-block elements. Together they cover 45 bond types, and we term this the BDE261 set. We have used these benchmark values to assess the performance of computationally less demanding theoretical procedures, including density functional theory (DFT), double-hybrid DFT (DHDFT), and high-level composite procedures. We find that the M06-2X (DFT), ROB2-PLYP and DuT-D3 (DHDFT), and G3X­(MP2)-RAD and G4­(MP2)-6X (composite) procedures yield absolute BDEs with satisfactory to excellent accuracy. Overall, we recommend G4­(MP2)-6X as an accurate and relatively cost-effective procedure for the direct computation of BDEs. One important finding is that the deviations for DFT and (especially) DHDFT procedures are often quite systematic. This allows an alternative approach to obtaining accurate absolute BDEs, namely, to evaluate accurate relative BDEs (RBDEs) using a computationally less demanding procedure, and to use these RBDEs in combination with appropriate and accurate reference BDEs to give accurate absolute BDEs. We recommend DuT-D3 for this purpose. For a still less computationally demanding approach, we introduce the deviation from additivity of the RBDE (DARBDE), and demonstrate that the combination of lower-level DARBDEs for larger systems and higher-level (W1w) reference RBDEs and BDEs for small systems can be utilized to obtain improved RBDEs for multiply substituted systems at low cost.本研究采用高阶W1w方案（W1w protocol），构建了包含261个键解离焓（bond dissociation enthalpies, BDEs）的综合数据集，所涉键型均为氢、第一周期与第二周期p区元素之间形成的化学键。该数据集共涵盖45种键型，我们将其命名为BDE261数据集。 我们借助这套基准数值，对计算成本较低的理论计算方法的性能进行了评估，涵盖密度泛函理论（DFT）、双杂化密度泛函理论（DHDFT）以及高阶复合计算方法三类。 研究发现，M06-2X（密度泛函理论方法）、ROB2-PLYP与DuT-D3（双杂化密度泛函理论方法），以及G3X(MP2)-RAD、G4(MP2)-6X（复合计算方法）所计算的绝对键解离焓均具有良好至优秀的精度。 综合来看，我们推荐采用G4(MP2)-6X作为一种精准且相对经济的直接计算键解离焓的方法。 一项关键结论是，DFT方法（尤其是DHDFT方法）的计算偏差往往具有较强的系统性。基于此，我们可通过另一种途径获取精准的绝对键解离焓：即先用计算成本较低的方法计算得到精准的相对键解离焓（relative BDEs, RBDEs），再将此类相对键解离焓与合适的精准参考键解离焓相结合，从而得到精准的绝对键解离焓。我们推荐采用DuT-D3方法用于该流程。 针对计算成本进一步降低的需求，我们提出了相对键解离焓加和性偏差（deviation from additivity of the RBDE, DARBDE）的概念，并证实：通过结合大体系的低阶DARBDEs、高阶（W1w）参考相对键解离焓，以及小体系的参考键解离焓，可以在极低计算成本下，为多取代体系得到更精准的相对键解离焓。