Surface-protecting ligands, as a major component of metal nanoclusters (MNCs), can dominate molecular characteristics, performance behaviors, and biological properties of MNCs, which brings diversity and flexibility to the nanoclusters and largely promotes their applications in optics, electricity, magnetism, catalysis, biology, and other fields. We report herein the design of a new kind of water-soluble luminescent gold nanoclusters (AuNCs) for enzyme-activatable charge transfer (CT) based on the ligand engineering of AuNCs with 6-mercaptopurine ribonucleoside (MPR). This elaborately designed cluster, Au₅(MPR)₂, can form a stable intramolecular CT state after light excitation, and exhibits long-lived color-tunable phosphorescence. After the cleavage by purine nucleoside phosphorylase (PNP), the CT triplet state can be easily directed to a low-lying energy level, leading to a bathochromic shift of the emission band accompanied by weaker and shorter-lived luminescence. Remarkably, these ligand-engineered AuNCs show high affinity towards PNP as well as decent performance for analyzing and visualizing enzyme activity and related drugs. The work of this paper provides a good example for diversifying physicochemical properties and application scenarios of MNCs by rational ligand engineering, which will facilitate future interest and new strategies to precisely engineer solution-based nanocluster materials.

中文翻译：

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金纳米簇中酶激活的电荷转移

表面保护配体作为金属纳米团簇（MNCs）的主要组成部分，可以主导MNCs的分子特性、性能行为和生物学特性，这给纳米团簇带来了多样性和灵活性，极大地促进了其在光学、电学、磁学等领域的应用。催化、生物学等领域。我们在此报告了一种基于 AuNC 与 6-巯基嘌呤核糖核苷 (MPR) 的配体工程设计的新型水溶性发光金纳米簇 (AuNC)，用于酶激活电荷转移 (CT)。这种精心设计的簇Au ₅ (MPR) ₂可以在光激发后形成稳定的分子内CT态，并表现出长寿命的颜色可调磷光。被嘌呤核苷磷酸化酶（PNP）裂解后，CT三重态很容易被引导至低能级，导致发射带红移，并伴随着较弱和较短寿命的发光。值得注意的是，这些配体工程化的 AuNC 对 PNP 表现出高亲和力，并且在分析和可视化酶活性和相关药物方面具有良好的性能。本文的工作为通过合理的配体工程实现跨国公司的理化性质和应用场景多样化提供了一个很好的例子，这将促进未来精确设计基于溶液的纳米团簇材料的兴趣和新策略。