Guidelines to calculate non-radiative deactivation mechanisms of ruthenium tris(bipyridine) derivatives

David Hernández-Castillo; Isabel Eder; Leticia González

doi:10.1016/j.ccr.2024.215819

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Title (eng)

Guidelines to calculate non-radiative deactivation mechanisms of ruthenium tris(bipyridine) derivatives

Author

David Hernández-Castillo

Department of Theoretical Chemistry, Faculty of Chemistry, University of Vienna

Isabel Eder

Department of Theoretical Chemistry, Faculty of Chemistry, University of Vienna

Leticia González

Department of Theoretical Chemistry, Faculty of Chemistry, University of Vienna

Abstract (eng)

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 ([Formula presented]) excited state or the ligand photorelease relies on the fine-tuning of the energetics of the higher-lying metal-centered excited states ([Formula presented]). In this contribution, we critically review different kinetic models commonly used to interpret the thermal activation of the [Formula presented] excited states from the lowest [Formula presented] minimum. Further, we extend our recently introduced kinetic model (Angew. Chem. Int. Ed. 2023, 62, e202308803) for [Formula presented] (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'-[Formula presented]-2,2'-bpy; R= [Formula presented], [Formula presented], [Formula presented], [Formula presented], [Formula presented] [Formula presented], and [Formula presented]), 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 [Formula presented] -trans conformation), while those with electron withdrawing ligands tend to decay through a different one (the [Formula presented]-cis Jahn-Teller isomer). We discuss structure/property relationships with focus on how to steer the energetics of the [Formula presented] excited states. This work opens the pathway to rationally use ligand substitution to enhance or quench the lifetimes of the [Formula presented] state and also provides guidelines to understand better non-radiative deactivation mechanisms in metal complexes.

Keywords (eng)

PhotophysicsRuthenium tris(bipyridine) complexesMetal-centered ligand-field excited statesJahn-Teller isomersTemperature-dependent photoluminescenceEmission lifetimes

Type (eng)

journal article

Language

English [eng]

Persistent identifier

https://phaidra.univie.ac.at/o:2068227

DOI

10.1016/j.ccr.2024.215819

Is in series

Title

Coordination Chemistry Reviews

Volume