ENS Paris-Saclay, Université Paris-Saclay CNRS, PPSM, 91190, Gif-sur-Yvette, France.
Université Paris Cité CNRS, ITODYS, 75013, Paris, France.
Chemistry. 2022 Dec 6;28(68):e202202071. doi: 10.1002/chem.202202071. Epub 2022 Oct 10.
Multichromophoric systems showing both fluorescence and photoisomerization are fascinating, with complex interchromophoric interactions. The experimental and theoretical study of a series of compounds, bearing a variable number of 4-dicyanomethylene-2-tert-butyl-6-(p-(N-(2-azidoethyl)-N-methyl)aminostyryl)-4H-pyran (DCM) units are reported. The photophysical properties of multi-DCM derivatives, namely 2DCM and 3DCM, were compared to the single model azido-functionalized DCM, in the E and Z isomers. The (EE)-2DCM and (EEE)-3DCM were synthesized via the click reaction. Steady-state spectroscopy and photokinetics experiments under UV or visible irradiation indicated the presence of intramolecular energy transfer processes among the DCM units. Homo- and hetero-energy transfer processes between adjacent chromophores were confirmed by fluorescence anisotropy and decays. Molecular dynamics simulations for 2DCM were carried out and analyzed using a Markov state model, providing geometrical parameters (orientation and distance between chromophores) and energy transfer efficiency. This work contributes to a better understanding and rationalization of multiple energy transfer processes occuring within multichromophoric systems.
多色体系同时表现出荧光和光致异构化现象，具有复杂的发色团间相互作用，非常引人注目。本研究报道了一系列化合物的实验和理论研究，这些化合物含有可变数量的 4-二氰基亚甲基-2-叔丁基-6-（p-（N-（2-叠氮乙基）-N-甲基）氨基苯乙烯基）-4H-吡喃（DCM）单元。比较了多 DCM 衍生物（即 2DCM 和 3DCM）与单模型叠氮功能化 DCM 的 E 和 Z 异构体的光物理性质。通过点击反应合成了（EE）-2DCM 和（EEE）-3DCM。在 UV 或可见光照射下进行稳态光谱和光动力学实验表明，DCM 单元之间存在分子内能量转移过程。通过荧光各向异性和衰减证实了相邻发色团之间的同分子和异分子能量转移过程。对 2DCM 进行了分子动力学模拟，并使用马尔可夫状态模型进行了分析，提供了几何参数（发色团的取向和距离）和能量转移效率。这项工作有助于更好地理解和合理化多色体系中发生的多个能量转移过程。
