Metal–thiolate complexes have been the focus of research for several years because of their unique photophysical properties and their use as a precursor for synthesizing various well-defined metal nanoclusters. A rational understanding of their structure–property relationship is necessary to realize their full potential in practical applications. Herein, we demonstrate the synthesis of a unique copper–thiolate complex with reversibly switchable catalytic and photoluminescence (PL) properties. The as-synthesized complex at basic pH (Complex B) showed cyan PL with a strong peak at ∼488 nm (cyan) and a small shoulder peak at ∼528 nm (green). When the pH of the complex was changed to acidic (Complex A), the PL was switched to light green. Such pH-responsive PL properties were demonstrated to be useful for pH and CO₂ sensing. The switchable properties originate from their two distinct structural states at two different pHs. We found that Complex A was resistant to high concentrations of a strong reducing agent, and had an intermediate oxidation state of copper (Cu⁺) with good thermodynamic stability. Furthermore, the switchable catalytic property was investigated with a 4-nitrophenol reduction and 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation reaction. The reduction kinetics followed pseudo-first-order, where the catalytic activity was enhanced by more than 10³ times when Complex B was switched to Complex A. A similar trend was also observed for TMB oxidation. Our design strategy demonstrates that redox switchable metal–thiolate complexes could be a powerful candidate for a plethora of applications.

中文翻译：

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通过耐还原发光铜-硫醇盐络合物实现可切换催化和 CO2 传感

金属-硫醇盐配合物多年来一直是研究的焦点，因为它们具有独特的光物理特性，并且可以用作合成各种明确定义的金属纳米团簇的前体。合理理解它们的结构-性质关系对于在实际应用中充分发挥其潜力是必要的。在此，我们展示了具有可逆切换催化和光致发光 (PL) 特性的独特硫醇铜络合物的合成。在碱性 pH 下合成的复合物（复合物 B）显示青色 PL，在 ~488 nm（青色）处有一个强峰，在~528 nm（绿色）处有一个小肩峰。当复合物的 pH 变为酸性时（复合物 A), PL 切换为浅绿色。这种 pH 响应 PL 特性被证明可用于 pH 和 CO ₂传感。可切换的特性源于它们在两个不同 pH 值下的两个不同结构状态。我们发现络合物 A能抵抗高浓度的强还原剂，并且铜 (Cu ⁺ ) 的中间氧化态具有良好的热力学稳定性。此外，通过 4-硝基苯酚还原和 3,3',5,5'-四甲基联苯胺 (TMB) 氧化反应研究了可切换的催化性能。还原动力学遵循准一级反应，当将复合物 B^切换为复杂的 A。TMB 氧化也观察到类似的趋势。我们的设计策略表明，氧化还原可切换金属-硫醇盐络合物可能是众多应用的有力候选者。