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Multiple Anti-Kasha Emissions in Transition-Metal Complexes

Tijdschriftbijdrage - Tijdschriftartikel

In this Letter, we present first-principles evidence that several higher-lying excited states are responsible for the emission spectrum of [M(CO)4(bpy)] (M = Cr, Mo, W and bpy = 2,2'-bipyrimidine) complexes. These results highlight the violation of Kasha's rule, which states that after irradiation, molecules emit light with appreciable yield only from their lowest energy excited state. Furthermore, in [W(CO)4(bpy)] and [Mo(CO)4(bpy)], the breaking of Kasha's rule is two-fold because at least two different excited states besides T1 are involved in emission. To our knowledge, these are the first transition-metal complexes unambiguously demonstrated to display simultaneous equilibrated and nonequilibrated anti-Kasha emissions. This work also highlights the complexity of the emissive processes of tetracarbonyl-diimine transition-metal complexes, which are controlled via a subtle interplay of electronic and geometrical effects along the excited-state deactivation dynamics.
Tijdschrift: Journal of Physical Chemistry Letters
Issue: 19
Volume: 10
Pagina's: 5798 - 5804
Aantal pagina's: 8
Jaar van publicatie:2019
Trefwoorden:Fysische scheikunde, Materiaalkunde, Atomaire, moleculaire en chemische natuurkunde