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A Look at Real‐World Transition‐Metal Thermochemistry and Kinetics with Local Hybrid Functionals

Grotjahn, Robin; Kaupp, Martin

Local hybrid functionals (LHs) use a position-dependent admixture of exact exchange in real space, which has previously been shown to offer various advantages over global hybrids and the potential to construct functionals with wide applicability. While main-group thermochemistry and kinetics and other properties have already been studied extensively, no broad and systematic investigation for the energetics of transition-metal complexes has been reported so far for LHs. To close this gap, we evaluate eight LHs for three previously reported test sets on barrier heights and reaction energies of real-world transition metal complexes, in comparison with several other rung-4 hybrid functionals. The recent LH20t-D4 method emerges as the top-performing functional for the overall benchmark, comparable to the simpler TPSS0-D4 and slightly before the more complex range-separated ωB97M-V. But LH20t-D4 and ωB97M-V perform much better for main-group energetics, making them overall more reliable tools to study organometallic reaction mechanisms. Given also its previously observed excellent performance for mixed-valence systems, LH20t-D4 is thus a widely applicable functional in both main-group and transition-metal chemistry, while also providing convincing accuracy for many spectroscopic properties. The earlier LH14t-calPBE-D4 local hybrid also performs well, while some first-generation LHs fall behind.
Published in: Israel Journal of Chemistry, 10.1002/ijch.202200021, Wiley-VCH