College of Chemistry and Materials Science, Jinan University, Guangzhou, 510632, China.
Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Guangdong-Hong Kong-Macau Joint Laboratory of Optoelectronic and Magnetic Materials, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China.
Adv Mater. 2023 Aug;35(33):e2303212. doi: 10.1002/adma.202303212. Epub 2023 Jul 3.
Development of type I photosensitizers (PSs) with strong hydroxyl radical ( OH) formation is particularly important in the anaerobic tumor treatment. On the other hand, it is challenging to obtain an efficient solid-state intramolecular motion to promote the development of molecular machine and molecular motor. However, the relationship between them is never revealed. In this work, a pyrazine-based near-infrared type I PS with remarkable donor-acceptor effect is developed. Notably, the intramolecular motions are almost maximized by the combination of intramolecular and intermolecular engineering to simultaneously introduce the unlimited bond stretching vibration and boost the group rotation. The photothermal conversion caused by the intramolecular motions is realized with efficiency as high as 86.8%. The D-A conformation of PS can also induce a very small singlet-triplet splitting of 0.07 eV, which is crucial to promote the intersystem crossing for the triplet sensitization. Interestingly, its photosensitization is closely related to the intramolecular motions, and a vigorous motion may give rise to a strong OH generation. In view of its excellent photosensitization and photothermal behavior, the biocompatible PS exhibits a superior imaging-guided cancer synergistic therapy. This work stimulates the development of advanced PS for the biomedical application and solid-state intramolecular motions.
开发具有强羟基自由基 ( OH) 生成能力的 I 型光动力剂（PS）在厌氧肿瘤治疗中尤为重要。另一方面，获得有效的固态分子内运动以促进分子机器和分子马达的发展极具挑战性。然而，它们之间的关系从未被揭示过。在这项工作中，开发了一种具有显著供体-受体效应的基于吡嗪的近红外 I 型 PS。值得注意的是，通过分子内和分子间工程的结合，几乎最大化了分子内运动，同时引入了无限的键拉伸振动并增强了基团旋转。分子内运动引起的光热转换效率高达 86.8%。PS 的 D-A 构象也可以诱导非常小的单重态-三重态分裂为 0.07 eV，这对于促进三重态敏化的系间窜越至关重要。有趣的是，其光致发光与分子内运动密切相关，剧烈的运动可能导致强烈的 OH 生成。鉴于其出色的光致发光和光热性能，生物相容性 PS 表现出优异的成像引导癌症协同治疗效果。这项工作激发了用于生物医学应用和固态分子内运动的先进 PS 的发展。
