Although a terminal oxyl species bound to certain metal ions is believed to be the intermediate for various oxidation reactions, such as O−O bond generation in photosystem II (PSII), such systems have not been characterized. Herein, we report a stable Zn^II–oxyl species induced by an MFI-type zeolite lattice and its reversible reactivity with O₂ at room temperature. Its intriguing characteristics were confirmed by in situ spectroscopic studies in combination with quantum-chemical calculations, namely analyses of the vibronic Franck–Condon progressions and the ESR signal features of both Zn^II–oxyl and Zn^II–ozonide species formed during this reversible process. Molecular orbital analyses revealed that the reversible reaction between a Zn^II–oxyl species and an O₂ molecule proceeds via a radical O–O coupling–decoupling mechanism; the unpaired electron of the oxyl species plays a pivotal role in the O−O bond generation process.

中文翻译：

---

MFI沸石中产生的稳定的ZnII-羟基物种的鉴定及其在室温下与O2的可逆反应性

尽管据信与某些金属离子结合的末端氧基物种是各种氧化反应的中间体，例如光系统II（PSII）中的O-O键生成，但尚未对此类系统进行表征。在本文中，我们报道了由MFI型沸石晶格诱导的稳定的Zn ^II-氧基物种及其在室温下与O _2的可逆反应性。它的有趣特征已通过原位光谱研究与量子化学计算相结合得到证实，即对Franck-Condon振动的分析以及Zn ^II –oxyl和Zn ^II的ESR信号特征。在该可逆过程中形成了–ozonide物种。分子轨道分析表明，Zn ^II-氧基物种与O ₂分子之间的可逆反应是通过自由基O-O偶联-去耦机制进行的。氧基物种的不成对电子在O-O键生成过程中起关键作用。