The applicability of ruthenium tris(bipyridine) complexes in fields like photoactivated chemotherapy or photocatalysis requires in-depth understanding of their excited state deactivation mechanism. In particular, the quenching of luminescence from the lowest triplet metal-to-ligand charge-transfer (▪) excited state or the ligand photorelease relies on the fine-tuning of the energetics of the higher-lying metal-centered excited states (▪). In this contribution, we critically review different kinetic models commonly used to interpret the thermal activation of the ▪ excited states from the lowest ▪ minimum. Further, we extend our recently introduced kinetic model (Angew. Chem. Int. Ed. 2023, 62, e202308803) for ▪ (bpy = 2,2'-bipyridine) to a set of homoleptic tris(bipyridine)ruthenium (II) derivatives. This set has been selected to cover a wide range of electron -withdrawing/-donating substituents in the periphery of the bipyridyl ligands (4,4'-▪-2,2'-bpy; R= ▪, ▪, ▪, ▪, ▪▪, and ▪), on the basis of the Hammett's constant of the R functional group. Our calculations show that complexes with electron donating groups decay predominantly via one Jahn-Teller isomer (the so-called ▪ -trans conformation), while those with electron withdrawing ligands tend to decay through a different one (the ▪-cis Jahn-Teller isomer). We discuss structure/property relationships with focus on how to steer the energetics of the ▪ excited states. This work opens the pathway to rationally use ligand substitution to enhance or quench the lifetimes of the ▪ state and also provides guidelines to understand better non-radiative deactivation mechanisms in metal complexes.

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三联吡啶钌衍生物非辐射失活机制计算指南

三联吡啶钌配合物在光活化化疗或光催化等领域的应用需要深入了解其激发态失活机制。特别是，来自最低三线态金属到配体电荷转移 (▪) 激发态或配体光释放的发光猝灭依赖于较高位置金属中心激发态 (▪) 能量的微调。在此贡献中，我们批判性地回顾了通常用于解释从最低 ▪ 最小值开始的 ▪ 激发态热激活的不同动力学模型。此外，我们将最近引入的 ▪ (bpy = 2,2'-联吡啶) 动力学模型 (Angew. Chem. Int. Ed. 2023, 62, e202308803) 扩展到一组均配三(联吡啶)钌 (II) 衍生物。该组已被选择以涵盖联吡啶配体外围的各种吸电子/供电子取代基（4,4'-▪-2,2'-bpy；R= ▪, ▪, ▪, ▪, ▪▪ 和▪)，基于R 官能团的哈米特常数。我们的计算表明，具有给电子基团的配合物主要通过一种 Jahn-Teller 异构体（所谓的 ▪ -反式构象）衰变，而具有吸电子配体的配合物则倾向于通过另一种异构体（▪-顺 Jahn-Teller 异构体）衰变。 ）。我们讨论结构/性质关系，重点是如何控制激发态的能量。这项工作开辟了合理使用配体取代来增强或淬灭状态寿命的途径，并为理解金属配合物中更好的非辐射失活机制提供了指导。