Ge Xiyang, Yin Yiyan, Sun Jianghui, Ouyang Jin, Na Na
Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University Beijing 100875 China
Chem Sci. 2023 Jan 26;14(8):2229-2236. doi: 10.1039/d2sc06915f. eCollection 2023 Feb 22.
Single electron transfer (SET) has made great contributions to a broad range of chemical processes, whose radical cation and carbocation intermediates are important for mechanism studies. Herein, hydroxyl radical (˙OH)-initiated SET was revealed in accelerated degradations, the online examination of radical cations and carbocations by electrosonic spray ionization mass spectrometry (ESSI-MS). In the green and efficient non-thermal plasma catalysis system (MnO-plasma), hydroxychloroquine was efficiently degraded upon SET carbocations. In the plasma field full of active oxygen species, ˙OH was generated on the MnO surface to initiate SET-based degradations. Furthermore, theoretical calculations revealed that ˙OH preferred to withdraw the electron from the N atom that was conjugated to the benzene ring. This facilitated the generation of radical cations through SET, which was followed by the sequential formation of two carbocations for accelerated degradations. Transition states and energy barriers were calculated to study the formation of radical cations and subsequent carbocation intermediates. This work demonstrates an ˙OH-initiated SET for accelerated degradation carbocations, providing a deeper understanding and the potential for the wider application of SET in green degradations.
单电子转移（SET）对广泛的化学过程做出了巨大贡献，其自由基阳离子和碳正离子中间体对机理研究很重要。在此，通过电喷雾电离质谱（ESSI-MS）对自由基阳离子和碳正离子进行在线检测，揭示了羟基自由基（˙OH）引发的SET在加速降解过程中的作用。在绿色高效的非热等离子体催化体系（MnO-等离子体）中，羟氯喹通过SET碳正离子被有效降解。在充满活性氧物种的等离子体场中，MnO表面产生˙OH以引发基于SET的降解。此外，理论计算表明˙OH更倾向于从与苯环共轭的N原子上夺取电子。这通过SET促进了自由基阳离子的生成，随后依次形成两个碳正离子以加速降解。计算了过渡态和能垒以研究自由基阳离子和随后的碳正离子中间体的形成。这项工作证明了˙OH引发的SET用于加速碳正离子降解，为SET在绿色降解中的更深入理解和更广泛应用提供了潜力。
