Rühe Jessica, Vinod Kavya, Hoh Hanna, Shoyama Kazutaka, Hariharan Mahesh, Würthner Frank
Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram 695551, India.
J Am Chem Soc. 2024 Sep 12. doi: 10.1021/jacs.4c08479.
The properties and functions of chromophores utilized by nature are strongly affected by the environment formed by the protein structure in the cells surrounding them. This concept is transferred here to host-guest complexes with the encapsulated guests acting as an environmental stimulus. A new cyclophane host based on coronene bisimide is presented that can encapsulate a wide variety of planar guest molecules with binding constants up to (4.29 ± 0.32) × 10 M in chloroform. Depending on the properties of the chosen guest, the excited state deactivation of the coronene bisimide chromophore can be tuned by the formation of host-guest complexes toward fluorescence, exciplex formation, charge separation, room-temperature phosphorescence (RTP), or thermally activated delayed fluorescence (TADF). The photophysical processes were investigated by UV/vis absorption, emission, and femto- and nanosecond transient absorption spectroscopy. To enhance the TADF, two different strategies were used by employing suitable guests: the reduction of the singlet-triplet gap by exciplex formation and the external heavy atom effect. Altogether, by using supramolecular host-guest complexation, a versatile multimodal chromophore system is achieved with the coronene bisimide cyclophane.
自然界中所利用的发色团的性质和功能，会受到其周围细胞中蛋白质结构所形成环境的强烈影响。在此，这一概念被应用于主客体复合物，其中被包封的客体充当环境刺激物。本文提出了一种基于并四苯双酰亚胺的新型环芳烷主体，它能够在氯仿中包封多种平面客体分子，结合常数高达(4.29±0.32)×10 M。根据所选客体的性质，通过形成主客体复合物，可将并四苯双酰亚胺发色团的激发态失活调节为荧光、激基复合物形成、电荷分离、室温磷光(RTP)或热激活延迟荧光(TADF)。通过紫外/可见吸收、发射以及飞秒和纳秒瞬态吸收光谱对光物理过程进行了研究。为了增强TADF，采用合适的客体使用了两种不同的策略：通过激基复合物形成降低单重态-三重态能隙以及外部重原子效应。总之，通过超分子主客体络合，利用并四苯双酰亚胺环芳烷实现了一种多功能的多模态发色团体系。
