镧系元素光致发光(PL)发射由于其特别有趣的特性而引起了技术和生物成像应用的广泛关注。例如窄的发射带和非常长的PL寿命。然而,这种发射过程需要从合适的天线进行能量传输的前一步骤。虽然生物相容性应用需要在水性介质中稳定的发光体,大多数基于镧系元素的发射体被水分子猝灭。以前,我们描述了一种小发光体,8-甲氧基-2-氧代-1,2,4,5-四氢环戊二烯[de]喹啉-3-膦酸(PAnt),它能够与Tb(III)和Eu(III)动态协调,与传统的镧系元素隐迹成像剂相比,其可交换行为提高了其在PL寿命成像显微镜(PLIM)中的性能。在这里,我们报告了一项深入的光物理和时间相关的密度泛函理论(TD-DFT)计算研究,该研究揭示了在水中形成的稳定复合物中Eu(III)和Tb(III)的不同敏化机制。了解水性介质中的这种独特行为可以探索生物成像或新型发射材料的不同应用。
Lanthanide photoluminescence (PL) emission has attracted much attention for technological and bioimaging applications because of its particularly interesting features, such as narrow emission bands and very long PL lifetimes. However, this emission process necessitates a preceding step of energy transfer from suitable antennas. While biocompatible applications require luminophores that are stable in aqueous media, most lanthanide-based emitters are quenched by water molecules. Previously, we described a small luminophore, 8-methoxy-2-oxo-1,2,4,5-tetrahydrocyclopenta[de]quinoline-3-phosphonic acid (PAnt), which is capable of dynamically coordinating with Tb(III) and Eu(III), and its exchangeable behavior improved their performance in PL lifetime imaging microscopy (PLIM) compared with conventional lanthanide cryptate imaging agents. Herein, we report an in-depth photophysical and time-dependent density functional theory (TD-DFT) computational study that reveals different sensitization mechanisms for Eu(III) and Tb(III) in stable complexes formed in water. Understanding this unique behavior in aqueous media enables the exploration of different applications in bioimaging or novel emitting materials.