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Oxidation-induced C-H bond activation in iridium pincer complexes
Alexey V Polukeev1, Magdalena Tasić1
1Centre for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden. alexey.polukeev@chem.lu.se.
Oxidizing iridium pincer complexes triggers C-H activation, forming new cyclometallated compounds. This research clarifies the mechanism involving proton loss, crucial for developing efficient dehydrogenation catalysts.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Electrochemistry
Background:
- Dehydrogenation reactions producing molecular hydrogen are thermodynamically unfavorable.
- Coupling dehydrogenation with green energy sources like oxygen or electricity is desirable.
- Understanding catalyst redox properties is key to enabling these reactions.
Purpose of the Study:
- To investigate the oxidation of iridium pincer complexes.
- To elucidate the mechanism of induced intramolecular C-H activation.
- To understand the redox properties of (POCOP)IrHCl and (PCP)IrHCl complexes.
Main Methods:
- Oxidation of iridium pincer complexes: (POCOP)IrHCl and (PCP)IrHCl.
- Electrochemical studies to probe redox properties.
- Density Functional Theory (DFT) calculations to model reaction mechanisms.
Main Results:
- Oxidation induced intramolecular C-H activation in the iridium pincer complexes.
- Formation of complexes featuring a cyclometallated tert-butyl group.
- Proposed mechanism involves H+ loss from hydrochlorides to yield a reactive (pincer)IrCl+ species.
Conclusions:
- The study reveals a novel pathway for C-H activation in iridium pincer complexes.
- The findings provide insights into the redox behavior of these catalysts.
- Understanding this mechanism is vital for designing efficient catalysts for hydrogen production.
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