Accurate Prediction of One-Electron Reduction Potentials in Aqueous Solution by Variable-Temperature H‑Atom Addition/Abstraction Methodology

A robust
and efficient theoretical approach for calculation of
the reduction potentials of charged species in aqueous solution is
presented. Within this approach, the reduction potential of a charged
complex (with a charge |n| ≥ 2) is probed
by means of the reduction potential of its neutralized (protonated/deprotonated)
cognate, employing one or several H-atom addition/abstraction thermodynamic
cycles. This includes a separation of one-electron reduction from
protonation/deprotonation through the temperature dependence. The
accuracy of the method has been assessed for the set of 15 transition-metal
complexes that are considered as highly challenging systems for computational
electrochemistry. Unlike the standard computational protocol(s), the
presented approach yields results that are in excellent agreement
with experimental electrochemical data. Last but not least, the applicability
and limitations of the approach are thoroughly discussed.