Sorbelli Diego, Belpassi Leonardo, Belanzoni Paola
Pritzker School of Molecular Engineering, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60615, United States.
CNR Institute of Chemical Science and Technologies "Giulio Natta" (CNR-SCITEC), Via Elce di Sotto 8, 06123 Perugia, Italy.
Inorg Chem. 2025 Jul 28;64(29):15193-15205. doi: 10.1021/acs.inorgchem.5c02310. Epub 2025 Jul 13.
A gold complex, [(PCP)Au-H] (PCP = 2,6-bis(di--butylphosphinomethyl)benzene), has been recently reported to insert O into the Au(III)-H bond, leading to a stable Au(III)-OOH complex with an observed kinetic behavior sharing similarities with those of previously reported Pd(II)-H (nonradical) and Pt(IV)-H (autoaccelerated radical chain) reactions with O. In this work, we computationally investigate, by inclusion of spin-orbit coupling (SOC) effects, along the adiabatic PES, this elusive reaction mechanism in connection with the Au(III)-H bond nature and in comparison with recent case studies involving isostructural Pd(II)-H ([(PCP)Pd-H]) or different ligand supported Au(III)-H ([(CNC)Au-H], CNC = 2,6-bis(alkylimidazol-2-ylidene)-pyridine) bonds. The M-H (M = Au, Pd) bonds in these complexes are shown to be mainly of electron-sharing nature, featuring, however, a decreasing degree of M(δ+)-H(δ-) polarization in the order [(PCP)Pd-H] > [(PCP)Au-H] > [(CNC)Au-H], which we propose to be related to their reactivity with dioxygen, with the M-H bond displaying no reactivity ([(CNC)Au-H]), a radical chain ([(PCP)Au-H]), and a nonradical ([(PCP)Pd-H]) reactivity. The decisive factors in dictating the M-H bond polarity and, consequently, the preferred pathway lie in the nature of both the ligand and the metal, demonstrating how the fine-tuning of the electronic structure of these complexes causes mechanistic pathways to diverge.
最近有报道称，一种金配合物[(PCP)Au-H]（PCP = 2,6-双（二-丁基膦甲基）苯）能将氧插入到Au(III)-H键中，生成一种稳定的Au(III)-OOH配合物，其观察到的动力学行为与先前报道的Pd(II)-H（非自由基）和Pt(IV)-H（自加速自由基链）与氧的反应相似。在这项工作中，我们通过纳入自旋轨道耦合（SOC）效应，沿着绝热势能面，对这种难以捉摸的反应机理进行了计算研究，该反应机理与Au(III)-H键的性质相关，并与最近涉及同结构Pd(II)-H（[(PCP)Pd-H]）或不同配体支持的Au(III)-H（[(CNC)Au-H]，CNC = 2,6-双（烷基咪唑-2-亚基）吡啶）键的案例研究进行了比较。这些配合物中的M-H（M = Au、Pd）键主要具有电子共享性质，然而，M(δ+)-H(δ-)极化程度按[(PCP)Pd-H] > [(PCP)Au-H] > [(CNC)Au-H]的顺序降低，我们认为这与它们与双氧的反应性有关，其中M-H键分别表现出无反应性（[(CNC)Au-H]）、自由基链反应性（[(PCP)Au-H]）和非自由基反应性（[(PCP)Pd-H]）。决定M-H键极性并因此决定首选反应途径的决定性因素在于配体和金属的性质，这表明了这些配合物电子结构的微调如何导致反应机理途径的分歧。
