@article{Alberto_Iannuzzi_Gurdal_Probst_2019, title={[Coᴵᴵ(BPyPy₂COH)(OH₂)₂]²⁺: A Catalytic Pourbaix Diagram and AIMD Simulations on Four Key Intermediates}, volume={73}, url={https://www.chimia.ch/chimia/article/view/2019_906}, DOI={10.2533/chimia.2019.906}, abstractNote={<p>Proton reduction by [Co<sup>II</sup>(BPyPy<sub>2</sub>COH)(OH<sub>2</sub>)<sub>2</sub>]<sup>2+</sup> (BPyPy<sub>2</sub>COH = [2,2’-bipyridin]-6-yl-di[pyridin-2-yl]methanol) proceeds through two distinct, pH-dependent pathways involving proton-coupled electron transfer (PCET), reduction and protonation steps. In this account we give an overview of the key mechanistic aspects in aqueous solution from pH 3 to 10, based on electrochemical data, time-resolved spectroscopy and <em>ab initio</em> molecular dynamics simulations of the key catalytic intermediates. In the acidic pH branch, a PCET to give a Co<sup>III</sup> hydride is followed by a reduction and a protonation step, to close the catalytic cycle. At elevated pH, a reduction to Co<sup>I</sup> is observed, followed by a PCET to a Co<sup>II</sup> hydride, and the catalytic cycle is closed by a slow protonation step. In our simulation, both Co<sup>I</sup> and Co<sup>II</sup>–H feature a strong interaction with the surrounding solvent via hydrogen bonding, which is expected to foster the following catalytic step.</p>}, number={11}, journal={CHIMIA}, author={Alberto, Roger and Iannuzzi, Marcella and Gurdal, Yeliz and Probst, Benjamin}, year={2019}, month={Nov.}, pages={906} }