Assessment of DFT methods for computing activation energies of Mo/W-mediated reactions

Using high level ab initio coupled cluster calculations as reference, the performances of 15 commonly used density functionals (DFs) on activation energy calculations for typical Mo/W-mediated reactions have been systematically assessed for the first time in this work. The selected representative Mo/W-mediated reactions cover a wide range from enzymatic reactions to organometallic reactions, which include Mo-catalyzed aldehyde oxidation (aldehyde oxidoreductase), Mo-catalyzed dimethyl sulfoxide (DMSO) reduction (DMSO reductase), W-catalyzed acetylene hydration (acetylene hydratase), Mo/W-mediated olefin metathesis, Mo/W-mediated olefin epoxidation, W-mediated alkyne metathesis, and W-mediated C-H bond activation. Covering both Mo- and W-mediated reactions, four DFs of B2GP-PLYP, M06, B2-PLYP, and B3LYP are uniformly recommended with and without DFT empirical dispersion correction. Among these four DFs, B3LYP is notably improved in performance by DFT empirical dispersion correction. In addition to the absolute value of calculation error, if the trend of DFT results is also a consideration, B2GP-PLYP, B2-PLYP, and M06 keep better performance than other functionals tested and constitute our final recommendation of DFs for both Mo- and W-mediated reactions.