Luminescent emitters based on lanthanide ions are of ubiquitous importance in the biological sciences, but typically need sensitisation from a covalently attached adjacent chromophore – an “antenna” – to have suitable emission intensities. Here we show that the mechanical bond can be used to connect the antenna to the emitter, providing unique dynamic features and stimuli-responsiveness to the resulting assemblies. We outline a strategy to synthesise [2]rotaxanes capped with strong chelating groups, and establish that post-functionalisation of the interlocked scaffold by lanthanide ion insertion is modular, high-yielding and straightforward. Photophysical studies revealed effective antenna-emitter energy transfer within the [2]rotaxane, and the sensitisation mechanism as well as ring-thread dynamics were studied with spectroscopic and computational methods. The rotaxane was shown to have high selectivity towards Cu(II) ions, acting as an efficient turn-off sensor. This study validates the mechanical bond as a conjugation method between antennas and emitters, yielding otherwise hard-to-access and beneficial features to the resulting molecular systems.

中文翻译：

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用机械键调制镧系元素发光：紧凑 [2]轮烷中的天线-发射器限制

基于镧系元素离子的发光发射器在生物科学中无处不在，但通常需要来自共价连接的相邻发色团（“天线”）的敏化才能获得合适的发射强度。在这里，我们展示了机械结合可用于将天线连接到发射器，从而为生成的组件提供独特的动态特性和刺激响应能力。我们概述了一种合成具有强螯合基团的 [2] 轮烷的策略，并确定通过镧系元素离子插入对互锁支架进行功能化是模块化的、高产率的和直接的。光物理研究揭示了 [2] 轮烷内有效的天线-发射器能量转移，并且使用光谱和计算方法研究了敏化机制以及环线动力学。研究显示，轮烷对 Cu（II） 离子具有高选择性，可作为一种高效的关断传感器。这项研究验证了机械键作为天线和发射器之间的共轭方法，从而为所得的分子系统产生了原本难以接近的有益特征。