UHasselt-Hasselt University, Institute for Materials Research (IMO), Design & Synthesis of Organic Semiconductors (DSOS), Agoralaan, 3590, Diepenbeek, Belgium.
IMEC, Associated Lab IMOMEC, Wetenschapspark 1, 3590, Diepenbeek, Belgium.
Chemistry. 2020 Nov 26;26(66):15212-15225. doi: 10.1002/chem.202002549. Epub 2020 Oct 16.
Boron dipyrromethene (BODIPY) dyes represent a particular class within the broad array of potential photosensitizers. Their highly fluorescent nature opens the door for theragnostic applications, combining imaging and therapy using a single, easily synthesized chromophore. However, near-infrared absorption is strongly desired for photodynamic therapy to enhance tissue penetration. Furthermore, singlet oxygen should preferentially be generated without the incorporation of heavy atoms, as these often require additional synthetic efforts and/or afford dark cytotoxicity. Solutions for both problems are known, but have never been successfully combined in one simple BODIPY material. Here, we present a series of compact BODIPY-acridine dyads, active in the phototherapeutic window and showing balanced brightness and phototoxic power. Although the donor-acceptor design was envisioned to introduce a charge transfer state to assist in intersystem crossing, quantum-chemical calculations refute this. Further photophysical investigations suggest the presence of exciplex states and their involvement in singlet oxygen formation.
硼二吡咯亚甲基（BODIPY）染料是潜在光敏剂中一个特殊的类别。它们高度荧光的特性为诊断和治疗的联合应用打开了大门，使用单一的、易于合成的发色团进行成像和治疗。然而，近红外吸收强烈需要用于光动力治疗，以增强组织穿透。此外，应该优先生成单线态氧，而不掺入重原子，因为这些原子通常需要额外的合成努力和/或提供暗毒性。这两个问题都有解决方案，但从未在一个简单的 BODIPY 材料中成功结合。在这里，我们提出了一系列紧凑的 BODIPY-吖啶二聚体，在光疗窗口中具有活性，并表现出平衡的亮度和光毒性。尽管供体-受体设计旨在引入电荷转移态以辅助系间窜跃，但量子化学计算否定了这一点。进一步的光物理研究表明存在激基复合物态，并且它们参与单线态氧的形成。
