Microkinetic Model as a Crucial Tool for Understanding Homogeneous Catalysis

Abstract

Microkinetic modeling is a computational tool that allows simulating the evolution of the concentration of catalytically relevant species with time, providing a description of the catalytic system closer to the experimental. Microkinetic models have been mainly applied in organometallic catalysis as a means for validating mechanistic proposals by comparing experimental and computed rates and concentrations at a given time. However, this tool becomes very useful when studying complicated reaction mechanisms, aiding in identifying the catalyst resting state, optimizing reaction conditions or improving the catalyst design. In this Concept, we focus on these applications of microkinetic modeling through the discussion of some selected examples. In addition, we also point out some of the challenges and limitations we may face when building microkinetic models, which may explain why they are still underused.

The Subtle Mechanism of Nickel-Photocatalyzed C(sp3)–H Cross-Coupling

“…The free-energy profile in Figure assumes that the approach of the THF • radical to the Ni complexes is barrierless. This is not exactly the case because these types of steps have been shown to have low barriers . We report the full free-energy profile for these reactions in the SI.…”

“…In the HTM proposal, there is only one photoactivation step, an energy transfer (EnT) step, and reductive elimination that takes place from a Ni II complex, which is, in fact, rather unusual . In view of this, we have carried out DFT calculations coupled with microkinetic modeling on the system reported by SD and reported in Scheme . We are aware of the differences in the nature of the halogen between the studies of SD and HTM, and we do not claim to be computing here the HTM system.…”