Heteroleptic (NHC/MIC) Biscarbene Ag(I) and Au(I) Complexes: Synthesis, Characterization and Catalytic Applications
Francisco J Ruiz-Mendoza1, Emmanuel Campos-Dominguez1, M Guadalupe Torres-Salazar1
1Área Académica de Química. Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km. 4.5, Mineral de la Reforma, Hidalgo, 42090, México.
Chempluschem
|January 31, 2025
Summary
New silver and gold biscarbene complexes were synthesized. Silver complexes catalyzed ketone-alkyne-amine coupling, while gold complexes excelled in aldehyde, amine, alkyne coupling and benzylic oxidation reactions.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Carbene Complexes
Background:
- Heterocyclic carbenes (NHCs) and mesoionic carbenes (MICs) are versatile ligands in organometallic chemistry.
- Silver(I) and gold(I) complexes are known for their catalytic activities in various organic transformations.
Purpose of the Study:
- To synthesize novel hetero-biscarbene silver(I) and gold(I) complexes.
- To investigate the catalytic applications of these new complexes in coupling reactions and oxidation processes.
Main Methods:
- Synthesis of [NHC-M-MIC]PF6 complexes (M=Ag, Au) via NHC-M-Cl precursors and in situ generated MICs.
- Full characterization using NMR spectroscopy, elemental analysis, melting point, and single crystal X-ray diffraction.
- Evaluation of catalytic activity in solvent-free KA2 coupling (Ag) and A3 coupling/benzylic oxidation (Au).
Main Results:
- Successful preparation and characterization of novel silver(I) and gold(I) hetero-biscarbene complexes.
- Silver(I) complexes efficiently catalyzed solvent-free KA2 coupling to yield quaternary carbon-containing propargyl amines.
- Gold(I) biscarbene complexes showed good performance in A3 coupling and benzylic oxidation with low catalyst loadings.
Conclusions:
- The synthesized hetero-biscarbene complexes represent a new class of catalysts.
- These complexes offer efficient catalytic pathways for important organic transformations, highlighting the potential of combining NHC and MIC ligands.
- The distinct catalytic behaviors of silver and gold complexes underscore the tunability of these systems for specific applications.
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