Wiethoff Maxim-Aleksa, Lezius Lena, Studer Armido
Organisch-Chemisches Institut, Universität Münster, 48149, Münster, Germany.
Angew Chem Int Ed Engl. 2025 Jun 2;64(23):e202501757. doi: 10.1002/anie.202501757. Epub 2025 Apr 26.
Electron donors that can be excited to higher energy states through light absorption can achieve oxidation potentials as low as -3.0 V (vs. SCE). However, ground-state organic electron transfer reagents operating at such potentials remain underdeveloped, often necessitating multi-step syntheses and elevated reaction temperatures for activation. The longer lifetime of ground-state reagents is an advantage compared to most photoexcited single-electron reductants, which typically have relatively short lifetimes. In this study, catalytically generated phosphine oxide radical anions derived from phosphines and water applying redox catalysis are introduced as highly efficient single-electron reductants. The in situ generated radical anions are capable of reducing electron-rich aryl chlorides at potentials as low as -3.3 V (vs. SCE). Cyclic voltammetry studies and DFT calculations provide valuable insights into the behavior of these phosphorus-based ground-state electron donors. These findings do not only expand the chemistry of phosphoranyl radicals but also unlock the potential of in situ generated organic ground state electron donors that reach potentials comparable to elemental potassium.
通过光吸收可被激发到更高能态的电子供体能够实现低至 -3.0 V（相对于标准甘汞电极）的氧化电位。然而，在这种电位下运行的基态有机电子转移试剂仍未得到充分发展，通常需要多步合成以及升高反应温度来活化。与大多数光激发单电子还原剂相比，基态试剂更长的寿命是一个优势，光激发单电子还原剂通常具有相对较短的寿命。在本研究中，引入了通过氧化还原催化由膦和水衍生的催化生成的氧化膦自由基阴离子作为高效单电子还原剂。原位生成的自由基阴离子能够在低至 -3.3 V（相对于标准甘汞电极）的电位下还原富电子芳基氯化物。循环伏安法研究和密度泛函理论计算为这些基于磷的基态电子供体的行为提供了有价值的见解。这些发现不仅扩展了磷酰基自由基的化学性质，还开启了原位生成的有机基态电子供体的潜力，这些电子供体可达到与金属钾相当的电位。
