Nussbaum Bryce C, Cavicchi Cameron R, Smith Mark D, Pellechia Perry J, Peryshkov Dmitry V
Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St, Columbia, South Carolina 29208, United States.
Inorg Chem. 2024 Jul 27. doi: 10.1021/acs.inorgchem.4c02022.
In this work, we report the first example of the PCET reactivity for a boron cluster compound, the zwitterionic -carboranyl diphosphonium derivative 7-P(H)Bu-10-P(H)Pr--CBH. This main-group reagent efficiently transfers two electrons and two protons to quinones to yield hydroquinones and regenerate a neutral -carboranyl diphosphine, 1-PBu-2-PPr--CBH. As we have previously reported the conversion of this -carboranyl diphosphine into the zwitterionic derivative upon reaction with main group hydrides, the transformation reported herein represents a complete synthetic cycle for the metal-free reduction of quinones, with the redox-active carboranyl diphosphine scaffold acting as a mediator. The proposed mechanism of this reduction, based on p determination, electrochemical studies, and kinetic isotope effect determination, involves the electron transfer from the - cluster to the quinone coupled with the delivery of protons.
在本工作中，我们报道了硼簇化合物两性离子型 - 碳硼烷基二鏻衍生物7-P(H)Bu-10-P(H)Pr--CBH的PCET反应性的首个实例。这种主族试剂能有效地将两个电子和两个质子转移给醌类，生成对苯二酚并再生中性的 - 碳硼烷基二膦1-PBu-2-PPr--CBH。正如我们之前报道的，这种 - 碳硼烷基二膦与主族氢化物反应时会转化为两性离子型衍生物，本文报道的转化代表了醌类无金属还原的完整合成循环，其中具有氧化还原活性的碳硼烷基二膦支架充当媒介。基于p测定、电化学研究和动力学同位素效应测定所提出的这种还原机制，涉及从 - 簇向醌的电子转移以及质子传递。
