Three-Coordinate Copper(II) Aryls: Key Intermediates in C-O Bond Formation
Subrata Kundu1, Christine Greene1, Kamille D Williams1
1Department of Chemistry, Georgetown University , Box 571227-1227, Washington, D.C. 20057, United States.
Journal of the American Chemical Society
|June 8, 2017
Summary
Novel copper(II) aryl complexes were synthesized and characterized. These intermediates react with nitric oxide and phenolate anions, enabling C-N bond formation and diaryl ether synthesis via unique copper-mediated pathways.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Synthetic Chemistry
Background:
- Copper(II) aryl species are crucial intermediates in copper-catalyzed cross-coupling reactions.
- Understanding their structure and reactivity is key to developing new synthetic methodologies.
Purpose of the Study:
- To synthesize and characterize novel three-coordinate copper(II) aryl complexes.
- To investigate the reactivity of these complexes with small molecules like nitric oxide and anions.
- To elucidate the mechanisms of C-N bond formation and diaryl ether synthesis.
Main Methods:
- Synthesis of copper(II) alkoxides and reaction with B(C6F5)3.
- Crystallographic, spectroscopic (NMR, EPR), and Density Functional Theory (DFT) studies.
- Reactions with gaseous nitric oxide (NO) and phenolate anions (PhO-).
Main Results:
- Formation of novel three-coordinate copper(II) aryls supported by beta-diketiminate ligands.
- Characterization revealing unique geometric and electronic structures of the Cu(II) organometallic complexes.
- Successful C-N bond formation with NO yielding [Cu](eta(2)-ONC6F5).
- Direct synthesis of diaryl ether (PhO-C6F5) from reaction with phenolate, involving redox disproportionation and formation of Cu(I) and transient Cu(III) species.
Conclusions:
- The synthesized copper(II) aryl complexes are versatile intermediates in organometallic transformations.
- The study provides mechanistic insights into copper-mediated C-N coupling and diaryl ether formation.
- This work expands the scope of reactivity for copper(II) organometallic compounds in catalysis.
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