Bistable [c2] daisy chain rotaxanes with respective extended and contracted forms of [c2]A and [c2]B containing a blue-emissive anthracene (AN) donor and orange-emissive indandione-carbazole (IC) acceptor were successfully synthesized via click reaction. Tunable-emission bistable [c2] daisy chain rotaxanes with fluorescence changes from blue to orange, including bright-white-light emissions, could be modulated by the aggregation-induced emission (AIE) characteristics and Förster resonance energy transfer (FRET) processes through altering water fractions and shuttling processes (i.e., acid/base controls). Accordingly, as a result of excellent fine-tuning AIE (at 60% water content of H₂O/THF) and FRET (with a compatible energy transfer of E_FRET = 33.2%) behaviors after the shuttling process (by adding base), the brightest white-light emission at CIE (0.31, 0.37) with a quantum yield of Φ = 15.64% was obtained in contracted [c2]B with good control of molecular shuttling to possess higher photoluminescence (PL) quantum yields and better energy transfer efficiencies (i.e., the manipulation of reduced PET and enhanced FRET processes) due to their intramolecular aggregations of blue AN donors and orange IC acceptors with a proper water content of 60% H₂O. Furthermore, dynamic light-scattering (DLS) and time-resolved photoluminescence (TRPL) measurements, along with theoretical calculations, were utilized to investigate and confirm AIE and FRET phenomena of bistable [c2] daisy chain rotaxanes. Especially, both bistable [c2] daisy chain rotaxanes [c2]A and [c2]B and noninterlocked monomer M could be exploited for the applications of ratiometric fluorescence temperature sensing due to the temperature effects on the AIE and FRET features. Based on these desirable bistable [c2] daisy chain rotaxane structures, this work provides a potential strategy for the future applications of tunable multicolor emission and ratiometric fluorescence temperature-sensing materials.

中文翻译：

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用于白光发射和温度传感应用的双稳态 [c2] 菊花链轮烷的可控聚集诱导发射和 Förster 共振能量转移行为

成功合成了双稳态 [ c 2 ] 菊花链轮烷，分别具有[ c 2 ]A和[ c 2 ]B的延伸和收缩形式，其中包含蓝色发射蒽 ( AN ) 供体和橙色发射茚满二酮-咔唑 ( IC ) 受体通过点击反应。可调发射双稳态 [ c2] 荧光从蓝色变为橙色的菊花链轮烷，包括亮白光发射，可以通过改变水分数和穿梭过程，通过聚集诱导发射 (AIE) 特性和 Förster 共振能量转移 (FRET) 过程进行调制（即酸/碱控制）。因此，由于在穿梭过程（通过添加碱）之后对AIE（H _{2 O/THF 的 60% 含水量）和 FRET（具有}E _FRET = 33.2%的兼容能量转移）行为进行了出色的微调，在收缩的[ c 2 ] B中获得了 CIE (0.31, 0.37) 处最亮的白光发射，量子产率为 Φ = 15.64%由于蓝色 AN 供体和橙色 IC 受体的分子内聚集与适当的水，具有良好的分子穿梭控制以拥有更高的光致发光 (PL) 量子产率和更好的能量转移效率（即，减少 PET 和增强的 FRET过程的操作）含量为 60% H ₂ O。此外，利用动态光散射 (DLS) 和时间分辨光致发光 (TRPL) 测量以及理论计算来研究和确认双稳态 [c 2] 菊花链的 AIE 和FRET现象轮烷。特别是，双稳态 [ c 2] 菊花链轮烷[ c 2 ]A和[由于温度对 AIE 和 FRET 特征的影响，c 2 ]B和非互锁单体M可用于比例荧光温度传感应用。基于这些理想的双稳态[ c 2]菊花链轮烷结构，这项工作为可调谐多色发射和比例荧光温度传感材料的未来应用提供了潜在的策略。