Alberto Roger, Iannuzzi Marcella, Gurdal Yeliz, Probst Benjamin
Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich.
Department of Bioengineering, Adana Alparslan Turkes Science and Technology University, Catalan Caddesi 201, Saricam, Adana, Turkey;, Email:
Chimia (Aarau). 2019 Nov 1;73(11):906-912. doi: 10.2533/chimia.2019.906.
Proton reduction by [Co(BPyPy₂COH)(OH₂)₂] (BPyPy₂COH = [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 molecular dynamics simulations of the key catalytic intermediates. In the acidic pH branch, a PCET to give a Co hydride is followed by a reduction and a protonation step, to close the catalytic cycle. At elevated pH, a reduction to Co is observed, followed by a PCET to a Co hydride, and the catalytic cycle is closed by a slow protonation step. In our simulation, both Co and Co-H feature a strong interaction with the surrounding solvent hydrogen bonding, which is expected to foster the following catalytic step.
[Co(BPyPy₂COH)(OH₂)₂]（BPyPy₂COH = [2,2'-联吡啶]-6-基-二[吡啶-2-基]甲醇）使质子还原的过程通过两个不同的、依赖于pH值的途径进行，这些途径涉及质子耦合电子转移（PCET）、还原和质子化步骤。在本报告中，我们基于电化学数据、时间分辨光谱以及关键催化中间体的分子动力学模拟，概述了在pH值为3至10的水溶液中的关键机理方面。在酸性pH分支中，通过PCET生成钴氢化物，随后是还原和质子化步骤，以完成催化循环。在较高pH值下，观察到钴被还原为Co，随后通过PCET生成钴氢化物，催化循环通过缓慢的质子化步骤完成。在我们的模拟中，Co和Co-H都与周围溶剂形成了强烈的氢键相互作用，这有望促进后续的催化步骤。
