• Home
  • Search Results
  • Peptide-tethered monodentate and chelating histidylidene metal complexes: synthesis and application in catalytic hydrosilylation.

Peptide-tethered monodentate and chelating histidylidene metal complexes: synthesis and application in catalytic hydrosilylation.

Dalton transactions (Cambridge, England : 2003) (2013-02-27)
Angèle Monney, Flavia Nastri, Martin Albrecht
ABSTRACT

The Nδ,Nε-dimethylated histidinium salt (His*) was tethered to oligopeptides and metallated to form Ir(III) and Rh(I) NHC complexes. Peptide-based histidylidene complexes containing only alanine, Ala-Ala-His*-[M] and Ala-Ala-Ala-His*-[M] were synthesised ([M] = Rh(cod)Cl, Ir(Cp*)Cl2), as well as oligopeptide complexes featuring a potentially chelating methionine and tyrosine residue, Met-Ala-Ala-His*-Rh(cod)Cl and Tyr-Ala-Ala-His*-Rh(cod)Cl. Chelation of the methionine-containing histidylidene ligand was induced by halide abstraction from the rhodium centre, while tyrosine remained non-coordinating under identical conditions. High catalytic activities in hydrosilylation were achieved with all peptide-based rhodium complexes. The cationic S(Met),C(His*)-bidentate peptide rhodium catalyst outperformed the monodentate neutral peptide complexes and constitutes one of the most efficient rhodium carbene catalysts for hydrosilylation, providing new opportunities for the use of peptides as N-heterocyclic carbene ligands in catalysis.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Iridium, powder, 99.9% trace metals basis
Sigma-Aldrich
Rhodium, powder, 99.95% trace metals basis
Sigma-Aldrich
Iridium, wire, diam. 0.15 mm, 99.9% trace metals basis
Sigma-Aldrich
Iridium, evaporation slug, diam. × L 0.6 cm × 1.2 cm, 99.9% trace metals basis
Sigma-Aldrich
Iridium, black, powder, −200 mesh, ≥99% trace metals basis
Sigma-Aldrich
Iridium, foil, thickness 0.25 mm, 99.9% trace metals basis
Sigma-Aldrich
Rhodium, foil, thickness 0.025 mm, 99.9% trace metals basis