title: Which Density Functional Is the Best in Computing C-H Activation Energies by Pincer Complexes of Late Platinum Group Metals?
abstract: Using the recently proposed corrective LCCSD(T) method as a reference, we systematically assess the widely used approximate density functionals to reproduce C-H bond activation barriers by pincer complexes of the late platinum group transition metals (TMs) (TM = Rh, Pd, Ir, Pt). The pincer ligands explored here cover a wide range of PNP, PCP, POCOP, NCN, and SCS types. Interestingly, B3LYP is found to be the most accurate functional, followed by several others previously identified as well-performing functionals, like B2GP-PLYP, B2-PLYP, and PBE0. However, all tested functionals were found to exhibit the following uniform trends: (1) the DFT barriers for reactions of group 9 TM (Rh and Ir) pincer complexes show higher accuracy compared with those for group 10 TM (Pd and Pt) reactions; (2) within the same group, 5d TM pincer complexes have higher accuracy than 4d TM ones. Consequently, the barriers for C-H activation by Pd(II) pincer complexes were found to be the least accurate among the four TMs in almost all functionals tested here. The DFT empirical dispersion correction (DFT-D3) is shown to have a very small effect on barrier height. This study has some implications for other σ-bond activations like H-H, C-C, and C-halogen bonds by late platinum group pincer complexes.
authors.affiliation: Department of Chemistry, Renmin University of China, Beijing, 100872, China.
authors.forename: Wenzhen
authors.initials: W
authors.lastname: Lai
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Jiannian
authors.initials: J
authors.lastname: Yao
authors.affiliation: Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel.
authors.forename: Sason
authors.initials: S
authors.lastname: Shaik
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen