Three‐Way Cooperativity in d8 Metal Complexes with Ligands Displaying Chemical and Redox Non‐Innocence |
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| Authors: | Dr Naina Deibel Stephan Hohloch Dr David Schweinfurth Fritz Weisser Dr Anita Grupp Prof?Dr Biprajit Sarkar |
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| Affiliation: | 1. Institut für Anorganische Chemie, Universit?t Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart (Germany);2. Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universit?t Berlin, Fabeckstrasse 34‐36, 14195, Berlin (Germany) |
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| Abstract: | Reversible proton‐ and electron‐transfer steps are crucial for various chemical transformations. The electron‐reservoir behavior of redox non‐innocent ligands and the proton‐reservoir behavior of chemically non‐innocent ligands can be cooperatively utilized for substrate bond activation. Although site‐decoupled proton‐ and electron‐transfer steps are often found in enzymatic systems, generating model metal complexes with these properties remains challenging. To tackle this issue, we present herein complexes (cod?H)M(μ‐L2?) M (cod?H)] (M=PtII, 1 ] or PdII, 2 ], cod=1,5‐cyclooctadiene, H2L=2,5‐di‐2,6‐(diisopropyl)anilino]‐1,4‐benzoquinone), in which cod acts as a proton reservoir, and L2? as an electron reservoir. Protonation of 2 ] leads to an unusual tetranuclear complex. However, 1 ] can be stepwise reversibly protonated with up to two protons on the cod?H ligands, and the protonated forms can be stepwise reversibly reduced with up to two electrons on the L2? ligand. The doubly protonated form of 1 ] is also shown to react with OMe? leading to an activation of the cod ligands. The site‐decoupled proton and electron reservoir sources work in tandem in a three‐way cooperative process that results in the transfer of two electrons and two protons to a substrate leading to its double reduction and protonation. These results will possibly provide new insights into developing catalysts for multiple proton‐ and electron‐transfer reactions by using metal complexes of non‐innocent ligands. |
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| Keywords: | bond activation electron transfer ligand effects quinones spectroelectrochemistry |
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