The redox property of the ultrasmall coinage nanoclusters (with several to tens of Au/Ag atoms) has elucidated the electron-transfer capacity of nanoclusters, and has been successfully utilized in a variety of redox conversions (such as from CO₂ to CO). Nevertheless, their biological applications are mainly restricted by the scarcity of atomically precise, water-soluble metal nanoclusters, and the limited application (mainly on the decomposition of H₂O₂ in these days). Herein, mercaptosuccinic acid (MSA) protected ultrasmall alloy AuAg nanoclusters were prepared, and the main product was determined [Au₃Ag₅(MSA)₃]⁻ by electrospray ionization mass spectrometry (ESI-MS). The clusters can not only mediate the decomposition of H₂O₂ to generate hydroxyl radicals, but is also able to mediate the reduction of nicotinamide adenine dinucleotide (NAD) to its reduced form of NADH. This is the first time that the atomically precise metal nanoclusters were used to mediate the coenzyme reduction. The preliminary mechanistic insights imply the reaction to be driven by the hydrogen bonding between the carboxylic groups (on the surface of MSA) and the amino N—H bonds (on NAD). In this context, the presence of the carboxylic groups, the sub-nanometer size regime (∼ 1 nm), and the synergistic effect of the Au-Ag clusters are pre-requisite to the NAD reduction.

超小型货币纳米团簇（具有数个至数十个Au/Ag原子）的氧化还原特性阐明了纳米团簇的电子转移能力，并已成功用于各种氧化还原转化（例如从CO 2 到CO _）。然而，它们的生物学应用主要受到缺乏原子级精确的水溶性金属纳米团簇和有限的应用（目前主要是H ₂ O ₂的分解）的限制。在此，制备了巯基琥珀酸（MSA）保护的超小合金AuAg纳米团簇，并测定了主要产物[Au ₃ Ag ₅ (MSA) ₃ ] ^-通过电喷雾电离质谱法 (ESI-MS)。该团簇不仅可以介导H ₂ O ₂分解产生羟基自由基，还可以介导烟酰胺腺嘌呤二核苷酸(NAD) 还原为其还原型NADH。这是首次使用原子级精确的金属纳米团簇来介导辅酶还原。初步的机理见解暗示反应是由羧基（在 MSA 表面）和氨基 N-H 键（在 NAD 上）之间的氢键驱动的。在这种情况下，羧基的存在、亚纳米尺寸范围（~ 1 nm）以及 Au-Ag 簇的协同效应是 NAD 还原的先决条件。