Acetonitrile Ligand Photosubstitution in Ru(II) Complexes Directly from the 3 MLCT State
Acetonitrile Ligand Photosubstitution in Ru(II) Complexes Directly from the 3 MLCT State
复制标题
直接来自 3 MLCT 态的 Ru(II) 配合物中的乙腈配体光取代
DOI：
10.1021/jacs.2c07209
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发表时间：
2022
影响因子：
15
通讯作者：
Turro, Claudia
中科院分区：
文献类型：
--
作者：
Steinke, Sean J.;Piechota, Eric J.;Loftus, Lauren M.;Turro, Claudia
通过Arrhenius分析，研究了含不同给电子能力的双齿配体L的[Ru（tpy）（L）（CH 3CN）]n+（1-11）（n= 1，2）系列化合物的激发态寿命随温度的变化关系.配合物1 - 11在450 nm照射下发生光诱导的CH 3CN解离，配体交换量子产率随着能量势垒的增加而增加，以从最低能量的三重态金属-配体电荷转移（3 MLCT）激发态填充解离的三重态配体场（3LF）态。结合密度泛函理论的计算结果表明，1 - 11中配体的光解离直接发生在3 MLCT态，而不是3LF态。这一发现是在对比普遍接受的机制配体光解钌（II）配合物，并表明光诱导配体解离的替代途径是可用的。这些结果可以广泛地影响需要配体光解离的应用的设计原则，例如光化学疗法和光化学疗法，以及那些不希望光取代的应用，例如太阳能转换。
The excited states of the series [Ru(tpy)(L)(CH3CN)]n+(1–11) (n= 1, 2) containing bidentate ligands L with varying electron-donating ability were characterized through Arrhenius analysis of the temperature dependence of their excited-state lifetimes. Complexes1–11undergo photoinduced CH3CN dissociation upon 450 nm irradiation with ligand exchange quantum yields that increase with the energy barrier to populating a dissociative triplet ligand field (3LF) state from the lowest-energy triplet metal-to-ligand charge transfer (3MLCT) excited state. Combined with DFT calculations, the data indicate that ligand photodissociation in1–11occurs directly from the3MLCT state instead of a3LF state. This finding is in contrast to the generally accepted mechanism for ligand photodissociation in Ru(II) complexes and indicates that alternative pathways for photoinduced ligand dissociation are available. These results can widely impact design principles for applications that require ligand photodissociation, such as photochemotherapy and photocatalysis, as well as for those where photosubstitution is undesirable, such as solar energy conversion.