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[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
Published on: May 21, 2019
K⋅⋅⋅F/O interactions bridge copper(I) fluorinated alkoxide complexes and facilitate dioxygen activation
June S Lum1, Laleh Tahsini, James A Golen
1Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|March 21, 2013
Summary
Potassium ions in copper(I) complexes promote oxygen reduction via aggregation, leading to C-H hydroxylation and CO2 reactivity. This study reveals novel copper-oxygen chemistry influenced by potassium cation interactions.
Area of Science:
- Organometallic Chemistry
- Coordination Chemistry
- Fluorinated Ligand Chemistry
Background:
- Copper(I) complexes are known for their diverse reactivity.
- Understanding the influence of counterions on metal complex reactivity is crucial.
- Fluorinated ligands can impart unique electronic and steric properties to metal complexes.
Purpose of the Study:
- To synthesize and characterize novel copper(I) complexes with fluorinated alkoxide ligands.
- To investigate the reactivity of these copper(I) complexes with molecular oxygen (O2).
- To elucidate the role of the counterion (K+, {K(18C6)}+, Ph4P+) in mediating oxygen activation and subsequent reactions.
Main Methods:
- Synthesis of seven E[Cu(OR)2] copper(I) complexes.
- Manometric studies at -78 °C to quantify oxygen uptake.
- Solution conductivity measurements to assess electrolyte behavior.
- Bond valence analysis to understand cation-ligand interactions.
- Isolation and characterization of a copper(II) carbonate product.
Main Results:
- K[Cu(OR)2] complexes react with O2 to form 2:1 and 3:1 Cu/O2 adducts, dependent on copper concentration.
- {K(18C6)}+ and Ph4P+ derivatives do not exhibit analogous O2 reactivity.
- K+ ions induce aggregation of [Cu(OR)2](-) units via K⋅⋅⋅F/O interactions, facilitating irreversible O2 reduction.
- Intramolecular hydroxylation of ligand C-H bonds and nucleophilic reaction with CO2 by oxygenated species were observed.
- A Cu(II) carbonate complex was successfully isolated and characterized.
Conclusions:
- Potassium ions play a critical role in activating copper(I) complexes for O2 reduction through aggregation.
- The observed K⋅⋅⋅F/O interactions are key to the unique reactivity of K[Cu(OR)2] species.
- These findings open avenues for developing novel catalysts for oxidation and carbonylation reactions using copper complexes.
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