Rajamalli Pachaiyappan, Rizzi Federica, Li Wenbo, Jinks Michael A, Gupta Abhishek Kumar, Laidlaw Beth A, Samuel Ifor D W, Penfold Thomas J, Goldup Stephen M, Zysman-Colman Eli
Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK.
Materials Research Centre, Indian Institute of Science, Bangalore, 560012, India.
Angew Chem Int Ed Engl. 2021 May 17;60(21):12066-12073. doi: 10.1002/anie.202101870. Epub 2021 May 3.
We report the characterization of rotaxanes based on a carbazole-benzophenone thermally activated delayed fluorescence luminophore. We find that the mechanical bond leads to an improvement in key photophysical properties of the emitter, notably an increase in photoluminescence quantum yield and a decrease in the energy difference between singlet and triplet states, as well as fine tuning of the emission wavelength, a feat that is difficult to achieve when using covalently bound substituents. Computational simulations, supported by X-ray crystallography, suggest that this tuning of properties occurs due to weak interactions between the axle and the macrocycle that are enforced by the mechanical bond. This work highlights the benefits of using the mechanical bond to refine existing luminophores, providing a new avenue for emitter optimization that can ultimately increase the performance of these molecules.
我们报道了基于咔唑 - 二苯甲酮热激活延迟荧光发光体的轮烷的表征。我们发现，机械键导致发射体的关键光物理性质得到改善，特别是光致发光量子产率增加，单重态和三重态之间的能量差减小，以及发射波长的微调，这是使用共价连接的取代基时难以实现的壮举。由X射线晶体学支持的计算模拟表明，这种性质的调节是由于轴与大环之间由机械键增强的弱相互作用而发生的。这项工作突出了使用机械键来优化现有发光体的好处，为发射体优化提供了一条新途径，最终可以提高这些分子的性能。
