Revelation of the photoactive species in the photocatalytic dimerization of - méthylstyrene by a dinuclear ruthenium-palladium complex
Résumé
A quantum chemical study of the photocatalytic dimerization of α-methylstyrene catalyzed by a dinuclear ruthenium-palladium complex was performed at the DFT/TD-DFT level in order to find the key steps of the catalytic reaction. This study reveals that the second insertion of α-methylstyrene is the rate-determining step and that it proceeds via triplet excited states of an intermediate complex. These excited states have geometries significantly different from that of the reactant, especially within the coordination sphere of the Pd unit. Indeed, one Pd-carbon bond is considerably lengthened, favoring the insertion process. These results open up the possibilities to optimize the process by fine modulation of the catalyst structure.