Photocatalysis is one of the fastest growing fields in homogeneous catalysis. There are a number of molecules that can absorb light to access a long-lived excited state, which may then have a novel reactivity and open new reaction pathways. These concepts are currently being exploited in an increasing number of reactions, but the topic is still relatively unexplored by computational chemistry.<br/><br/>The theoretical approach to these photocatalytic problems is far from trivial, as there are issues of photoabsorption, crossing between electronic states and single electron transfer that require specific treatments, which are often computationally demanding and need expert treatment. There is however a wealth of information to gain from the use of relatively standard techniques. Our computational approach is based on standard DFT calculations (local minima and transition state location) on the reaction mechanism as the system descends from the excited-state reactants towards the products. These are complemented by TD-DFT calculations on the excitation process, estimation of single-electron transfer barriers by Marcus theory, and an extensive use of microkinetic models.<br/><br/>In this communication we will report our recent work in this field, both on organic an organometallic systems. In terms of photoorganotalytic processes, we will discuss the mechanistic characterization of photoinitiated aromatic perfluoroalkylation and light-driven benzylation of enals. In terms of transition metal systems, we will present our calculations on nickel-based catalysis using an external ruthenium photosensitizer. Recent results on photoactivated reactions of platinum and iron complexes will be also briefly analyzed.

Computational characterization of photocatalytic processes with DFT-based methods

2019 Fall National Meeting

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