Guilbaud Valentine, Kumar Prashant, Grosjean Alexis, Delfourne Evelyne, Boggio-Pasqua Martial, Mallet-Ladeira Sonia, Serpentini Charles-Louis, Benoist Eric, Dixon Isabelle M, Fery-Forgues Suzanne
SPCMIB, CNRS UMR 5068, Université de Toulouse, 118 route de Narbonne, 31062 Toulouse cedex 9, France.
Laboratoire de Chimie et Physique Quantiques (LCPQ), CNRS UMR 5626, Université de Toulouse, 118 route de Narbonne, 31062 Toulouse cedex 9, France.
Spectrochim Acta A Mol Biomol Spectrosc. 2026 Jan 5;344(Pt 1):126647. doi: 10.1016/j.saa.2025.126647. Epub 2025 Jul 3.
Photoactive rhenium(I) complexes have high therapeutic potential, particularly in the fight against cancer and antibiotic-resistant bacteria. They have the particularity of combining several modes of action, including photogeneration of carbon monoxide (CO) and singlet oxygen. However, their design is still to be improved. One limitation is that most of them absorb in the UV range, as is the case for Re-Pyta-TPP, a very attractive photochemically CO-releasing molecule (PhotoCORM). To shift absorption to the visible, an additional nitrogen atom was introduced into the pyridyltriazole bidentate ligand of this complex. The four resulting isomers Re-Ln-TPP (n = 1-4) were thus synthesized and studied from both an experimental and a theoretical point of view. Remarkably, their spectroscopic and photochemical properties strongly depend on the substitution pattern. Three out of four complexes can indeed be excited in the visible. The photodecarbonylation yield of the new complexes was lower than that of Re-Pyta-TPP. Interesting links were found between absorption and photoluminescence data, and photoreactivity. DFT and TD-DFT calculations provided rational bases to these observations, showing that the quantum yield for CO photorelease can be correlated to the potential energy profile for the complexes in their lowest triplet state. The Re-Ln-TPP complexes that absorb and emit at the longest wavelengths have the best singlet oxygen photoproduction. This shows that it is not easy to optimize all the spectroscopic and photochemical properties at once, and that a fair balance must be found between them. This study is another step towards rationally-designed photoCORMs.
光活性铼（I）配合物具有很高的治疗潜力，特别是在对抗癌症和耐抗生素细菌方面。它们具有结合多种作用方式的特殊性，包括一氧化碳（CO）和单线态氧的光生成。然而，它们的设计仍有待改进。一个限制是，它们中的大多数在紫外范围内吸收，例如极具吸引力的光化学一氧化碳释放分子（光化学一氧化碳释放分子，PhotoCORM）Re-Pyta-TPP就是如此。为了将吸收波段转移到可见光范围，在该配合物的吡啶基三唑双齿配体中引入了一个额外的氮原子。由此合成了四种异构体Re-Ln-TPP（n = 1-4），并从实验和理论两个角度进行了研究。值得注意的是，它们的光谱和光化学性质强烈依赖于取代模式。四种配合物中有三种确实可以在可见光下被激发。新配合物的光脱羰产率低于Re-Pyta-TPP。在吸收和光致发光数据以及光反应性之间发现了有趣的联系。密度泛函理论（DFT）和含时密度泛函理论（TD-DFT）计算为这些观察结果提供了合理的依据，表明CO光释放的量子产率可以与配合物在其最低三重态的势能分布相关联。在最长波长处吸收和发射的Re-Ln-TPP配合物具有最佳的单线态氧光生成能力。这表明要同时优化所有光谱和光化学性质并不容易，必须在它们之间找到合理的平衡。这项研究是朝着合理设计光化学一氧化碳释放分子迈出的又一步。
