AIDE – Design of aggregation-induced dually emissive bichromophores

该项目的目的是开发具有双发射或环境敏感混合颜色发射的非离子双显色发光体。因此，本文构思了以多样性为导向的新型双生色团文库的合成，并借助量子化学模拟手段，系统地研究了由不同取代的花菁和三芳胺组成的双色团的聚集诱导双发射(AIDE)的分子结构参数。两个共价结合的发色团(供体：UV/VIS吸收，蓝色发射；受体：红移吸收，长波发射)被放置在Förster半径内，当供体的发射带和受体的吸收带光谱重叠时，能量从“蓝色”供体转移到“红色”受体。红色受体的选择将使其在具有可变极性和/或正规性的溶剂混合物中聚集时发射明显增加。这些双色团体系的发光颜色可以通过供体和受体之间能量转移的效率以及受体的发射效率与其聚集程度的关系来调节。因此，受体的部分能量转移和聚集诱导发射(AIE)是获得供体和受体共同贡献的双重发射的前提条件。目标A)AIE辅助双色团体系合成策略的方法学发展；B)具有明显AIE性质的花青基结构的光谱鉴定；受体和双色团体系的辅助性质以及相关的分子质量/环境参数，如极性和粘度，以及这些影响的温度依赖性；利用光谱学方法，如时间分辨发射测量(ps到ns范围)和客户模拟(基于晶体结构分析的QM/MM处理)，详细研究了辅助对选定的双色团的作用机制D)稳定基于双发色团的聚集体的策略和水可分散的双色团纳米颗粒的制备和表征E)将在有机合成、物理有机化学和光谱学协同合作的基础上，对粒子表面的聚集进行研究，以预测标记的光学性质。

The aim of this project is the development of non-ionic bichromophoremitters with a dual emission or an environment-sensitive mixed color emission. Therefore, the diversity-oriented synthesis of novel bichromophore libraries is conceived and the systematic determination of molecular structural parameters of aggregation-induced dual emission (AIDE) of bichromophores constituted of diversely substituted merocyanines and triarylamines is studied by optical spectroscopy in solution, in particle systems and crystalline solids, assisted by quantum chemical modeling. Bichromophore emitters are envisioned showing environmental changes from aprotic vs protic or polar vs apolar by occurrence of mixed color emission that can be spectroscopically monitored.Two covalently bound emissive chromophores (donor: UV/vis-absorbing, blue emission; acceptor: red-shifted absorption, long wavelength emission) are placed within a Förster radius in a way that upon spectral overlap of the donor's emission band and the acceptor's absorp-tion band enables an energy transfer from „blue“ donor to „red“ acceptor. The red acceptor will be chosen such that its emission can be distinctly increased upon aggregation in solvent mixtures with variable polarity and/or proticity. The resulting emission color of these Bichromophore systems can be tuned by the efficiency of the energy transfer between donor and acceptor and by the efficiency of the acceptor's emission in dependence of its degree of aggregation. Therefore, partial energy transfer and aggregation-induced emission (AIE) of the acceptor are the prerequisites for the desired dual emission contributed by both donor and acceptor. The envisioned goals A) methodological development of the synthesis strategy for AIE-AIDE bichromophore systemsB) spectroscopic identification of merocyanine-based structures with particularly pronounced AIE properties of the acceptor and AIDE properties of the bichromophor system and the relevant molecular masses/environmental parameters such as polarity and viscosity and the temperature dependence of these influences; detailed investigations of the mechanism of the AIDE on selected bichromophores using spectroscopic methods such as time-resolved emission measurements (ps to ns range) and customer-based modelling (QM/MM treatment based on crystal structure analyses)C) mechanistic rationalization of the underlying energy transfer processesD) strategies for stabilization of bichromophore-based aggregates and preparation and characterization of water dispersible bichromophore nanoparticles E) aggregation studies on particle surfaces for prediction of the optical properties of markers on the basis of AIE-AIDE bichromophoreswill be achieved in synergetic collaboration between organic synthesis, physical organic chemistry and optical spectroscopy.