Evidence is provided for a previously unknown proton-coupled electron transfer (PCET) mechanism for nitric oxide (NO) release from endogenous S-Nitrosoglutathione (GSNO) catalyzed by the metal–organic framework (MOF) H₃[(Cu₄Cl)₃(BTTri)₈] (CuBTTri) in the presence of glutathione (GSH). The balanced reaction stoichiometry, active site characterization, and the experimental rate law are used to systematically disprove competing mechanistic hypotheses, leading unexpectedly to PCET as the proposed basic mechanism. The PCET mechanism contrasts traditionally proposed, either formally Cu^II to Cu^I redox or other formally Cu^II Lewis acid mechanisms for NO generation by other Cu-based catalysts. The proposed PCET mechanism sets the stage for mechanistically guided syntheses of improved Cu-MOF catalysts for GSNO to NO conversion and for computational investigations on the CuBTTri/GSNO/GSH/NO system as further tests of the well-defined structure of CuBTTri, structures of hypothesized reaction intermediates, and specific questions and hypotheses generated by the proposed PCET mechanism.

中文翻译：

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CuII Lewis 酸、质子耦合电子转移机制用于 Cu-金属-有机骨架催化的 S-亚硝基谷胱甘肽释放 NO

_{提供了以前未知的质子耦合电子转移 (PCET) 机制的证据，该机制用于由金属-有机骨架 (MOF) H 3} [(Cu ₄ Cl) _{3催化的内源性}S-亚硝基谷胱甘肽 (GSNO)释放一氧化氮 (NO) (BTTri) ₈ ] (CuBTTri) 在谷胱甘肽 (GSH) 的存在下。平衡的反应化学计量、活性位点表征和实验速率定律被用来系统地反驳相互竞争的机制假设，出乎意料地导致 PCET 作为提议的基本机制。PCET 机制对比传统上提出的，无论是形式上的 Cu ^II到 Cu ^I氧化还原还是其他形式上的 Cu ^II其他铜基催化剂产生 NO 的路易斯酸机理。所提出的 PCET 机制为机械引导合成改进的 Cu-MOF 催化剂以用于 GSNO 转化为 NO 以及对 CuBTTri/GSNO/GSH/NO 系统的计算研究奠定了基础，作为对明确定义的 CuBTTri 结构的进一步测试，假设的反应中间体，以及由所提出的 PCET 机制产生的具体问题和假设。