Department of Chemistry and RECETOX, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic.
J Org Chem. 2020 Aug 7;85(15):9776-9790. doi: 10.1021/acs.joc.0c01104. Epub 2020 Jul 22.
Heptamethine cyanines (Cy7) are fluorophores essential for modern bioimaging techniques and chemistry. Here, we systematically evaluated the photochemical and photophysical properties of a library of Cy7 derivatives containing diverse substituents in different positions of the heptamethine chain. A single substitution allows modulation of their absorption maxima in the range of 693-805 nm and photophysical properties, such as quantum yields of singlet-oxygen formation, decomposition, and fluorescence or affinity to singlet oxygen, within 2-3 orders of magnitude. The same substituent in different positions of the chain often exhibits distinctly contradictory effects, demonstrating that both the type and position of the substituent are pivotal for the design of Cy7-based applications. The combination of experimental results with quantum-chemical calculations provides insights into the structure-property relationship, the elucidation of which will accelerate the development of cyanines with properties tailored for specific applications, such as fluorescent probes and sensors, photouncaging, photodynamic therapy, or singlet-oxygen detection.
七甲川菁染料（Cy7）是现代生物成像技术和化学中必不可少的荧光团。在这里，我们系统地评估了包含在七甲川链不同位置的不同取代基的 Cy7 衍生物文库的光化学和光物理性质。单个取代基允许它们的吸收最大值在 693-805nm 的范围内进行调制，并且光物理性质（例如单线态氧形成、分解和荧光的量子产率或对单线态氧的亲和力）在 2-3 个数量级内进行调制。同一取代基在链的不同位置通常表现出明显相反的效果，这表明取代基的类型和位置对于基于 Cy7 的应用的设计都是至关重要的。将实验结果与量子化学计算相结合，提供了对结构-性质关系的深入了解，阐明这一关系将加速具有特定应用特性的菁染料的发展，例如荧光探针和传感器、光解笼、光动力疗法或单线态氧检测。
