Assessment of the applicability of DFT methods to [Cp*Rh]‐catalyzed hydrogen evolution processes

Abstract

AbstractThe present computational study provides a benchmark of density functional theory (DFT) methods in describing hydrogen evolution processes catalyzed by [Cp*Rh]‐containing organometallic complexes. A test set was composed of 26 elementary reactions featuring chemical transformations and bonding situations essential for the field, including the emerging concept of non‐innocent Cp* behavior. Reference values were obtained from a highly accurate 3/4 complete basis set and 6/7 complete PNO space extrapolated DLPNO‐CCSD(T) energies. The performance of lower‐level extrapolation procedures was also assessed. We considered 84 density functionals (DF) (including 13 generalized gradient approximations (GGA), nine meta‐GGAs, 33 hybrids, and 29 double‐hybrids) and three composite methods (HF‐3c, PBEh‐3c, and r2SCAN‐3c), combined with different types of dispersion corrections (D3(0), D3BJ, D4, and VV10). The most accurate approach is the PBE0‐DH‐D3BJ (MAD of 1.36 kcal mol−1) followed by TPSS0‐D3BJ (MAD of 1.60 kcal mol−1). Low‐cost r2SCAN‐3c composite provides a less accurate but much faster alternative (MAD of 2.39 kcal mol−1). The widely used Minnesota‐family M06‐L, M06, and M06‐2X DFs should be avoided (MADs of 3.70, 3.94, and 4.01 kcal mol−1, respectively).