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Updated: Aug 30, 2025
Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics
Published on: April 12, 2019
Mechanistic Studies for Pd(II)(O2) Reduction Generating Pd(0) and H2O: Formation of Pd(OH)2 as a Key Intermediate
Jeongmin Cha1, Eunsung Lee1,2, Dmitry V Yandulov2,3
1Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea.
Abstract:
Molecular oxygen (O2) remains to be an ideal yet underutilized feedstock for the oxidative transformation of organic substrates and renewable energy systems such as fuel cells. Palladium (Pd) has shown particular promise in enabling these applications. The present study describes a Pd-mediated O2 reduction to water via C-H activation of 9,10-dihydroanthracene (DHA) by a Pd(II) η2-peroxo complex 1O. The reaction yields stoichiometric anthracene and Pd(0) product 1 and is notable in two respects. First, plots of concentrations of the reaction participants over time have distinctly sigmoidal shapes, indicating that conversion accelerates over time and implying autocatalysis. Second, the reaction proceeds via a genuine monometallic Pd(II) dihydroxide 1(OH) directly observed to grow and decay as an intermediate. Confirming its role as an intermediate, the dihydroxide 1(OH) was found to mediate C-H oxidation of DHA on par in activity with the peroxo compound 1O. Mechanistic studies with density functional theory (DFT) calculations suggested that both 1O and 1(OH) react with DHA by hydrogen atom transfer (HAT) and that autocatalysis in the 1O reaction results from oxidative addition of the initial Pd(II) complex 1O to the Pd(0) product 1. This reaction forms a transient bis(μ-oxo) Pd(II) dimer 1O1 that is more active in the HAT oxidation of DHA than the initial 1O.
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