山东大学孙頔团队近日研究了具有光调制光致发光的可光切换芳唑基功能化Ag8纳米团簇。这一研究成果于2025年6月10日发表在《美国化学会杂志》上。

智能分子光开关是人工材料领域的一个重要成员，它在光照射下可以表现出独特的物理化学性质，但由于其固有的光不稳定性，光驱动银纳米开关很少被开发。

研究组合成了两种光稳定的等结构光响应Ag8纳米纳米管（Ag8a和Ag8b），其双头三角形棱柱形Ag8核由芳唑吡唑、芳基硫酸酯和二膦三元配体保护。芳唑吡唑的引入为银纳米计增加了新的功能，实现了光异构化开关光致发光。Ag8纳米微球在紫外和可见光照射下分别以较高的效率在反式和顺式构象之间进行可逆异构化，这种异构化可以发生在固体和溶液状态，并且可以方便地通过随时间变化的紫外-可见光谱进行监测。

更有趣的是，反式异构化过程伴随着发射带从橙色到红色的显着的色移。这项工作不仅为光响应银纳米材料的合成提供了战略指导，而且为开发光开关荧光材料提供了新的机遇。

附：英文原文

Title: Photoswitchable Arylazopyrazole-Functionalized Ag8 Nanoclusters with Light-Modulated Photoluminescence

Author: Tianyang Xu, Wei-Dan Si, Chengkai Zhang, Bao-Liang Han, Zhi Wang, Chen-Ho Tung, Di Sun

Issue&Volume: June 10, 2025

Abstract: Smart molecular photoswitches are an important member in the realm of artificial materials, which can exhibit distinct physicochemical properties under photoirradiation, yet light-driven silver nanocluster switches have been scarcely exploited due to their intrinsic photoinstability. Herein, two photostable isostructural photoresponsive Ag8 nanoclusters (Ag8a and Ag8b) with a bicapped triangular prismatic Ag8 core protected by the ternary ligands of arylazopyrazole, aryl-thiolate, and diphosphine have been synthesized and characterized comprehensively. The introduction of arylazopyrazole augments a fresh functionality to the silver nanocluster, realizing photoisomerization switched photoluminescence. The Ag8 nanoclusters can be reversibly isomerized between trans and cis conformations with quite high efficiency under UV and visible light irradiation, respectively, which can occur in both solid and solution states and be conveniently monitored by time-dependent UV–Vis spectroscopy. More interestingly, the trans–cis isomerization process is accompanied by a significant bathochromic shift of the emission band from orange to red. This work not only presents a strategic guidance for synthesizing photoresponsive silver nanoclusters but also provides a new opportunity for developing photoswitchable fluorescent materials.

DOI: 10.1021/jacs.5c01348

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c01348