The Effect of Hartree-Fock Exchange on Scaling Relations and Reaction Energetics for C–H Activation Catalysts
The Effect of Hartree-Fock Exchange on Scaling Relations and Reaction Energetics for C–H Activation Catalysts
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DOI：
10.1007/s11244-021-01482-5
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发表时间：
2021-06
影响因子：
3.6
通讯作者：
Vyshnavi Vennelakanti;Aditya Nandy;H. Kulik
中科院分区：
文献类型：
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作者：
Vyshnavi Vennelakanti;Aditya Nandy;H. Kulik
高通量计算催化剂的研究通常使用密度泛函理论(DFT)进行，其中只有一个近似的交换相关泛函。在具有挑战性反应(如C-H活化)的开壳过渡金属络合物(TMC)中，密度泛函的预测能力受到了挑战，而且性质强烈依赖于Hartree-Fock(HF)交换的混合物。我们开展了一项大规模的氢氟离子交换对1200多个中排(即，铬、锰、铁、钴)3dTMCs甲烷直接转化为甲醇的预测催化性能的研究。这组反应的能量敏感性取决于催化剂的催化重排和配体化学。这些灵敏度的差异既改变了对催化剂的绝对能量预测，也改变了催化剂的相对性能。以往关于全局线性自由能关系(LFER)性能较差的观察结果与半局部密度泛函被广泛应用于多相催化和混合密度泛函都是一致的。窄的金属/氧化/自旋态特定的LFER比绝对反应能级表现得更好，对HF交换不那么敏感，除了一些中/高自旋态的情况外。重要的是，自旋态相关反应能量学和交换效应对自旋态有序的相互作用意味着DFT泛函的选择强烈地影响着最小能量路径是否是自旋守恒的。尽管有这些警告，但使用有望具有闭壳中间体和低自旋基态的催化剂的LFER仍具有显著的预测能力。
High-throughput computational catalyst studies are typically carried out using density functional theory (DFT) with a single, approximate exchange-correlation functional. In open shell transition metal complexes (TMCs) that are promising for challenging reactions (e.g., C–H activation), the predictive power of DFT has been challenged, and properties are known to be strongly dependent on the admixture of Hartree-Fock (HF) exchange. We carry out a large-scale study of the effect of HF exchange on the predicted catalytic properties of over 1200 mid-row (i.e., Cr, Mn, Fe, Co) 3dTMCs for direct methane-to-methanol conversion. Reaction energy sensitivities across this set depend both on the catalytic rearrangement and ligand chemistry of the catalyst. These differences in sensitivities change both the absolute energetics predicted for a catalyst and its relative performance. Previous observations of the poor performance of global linear free energy relationships (LFERs) hold with both semi-local DFT widely employed in heterogeneous catalysis and hybrid DFT. Narrower metal/oxidation/spin-state specific LFERs perform better and are less sensitive to HF exchange than absolute reaction energetics, except in the case of some intermediate/high-spin states. Importantly, the interplay between spin-state dependent reaction energetics and exchange effects on spin-state ordering means that the choice of DFT functional strongly influences whether the minimum energy pathway is spin-conserved. Despite these caveats, LFERs involving catalysts that can be expected to have closed shell intermediates and low-spin ground states retain significant predictive power.