Switched Stereocontrol in Grubbs−Hoveyda Complex Catalyzed ROMP Utilizing Proton-Switched NHC Ligands

Autor:	Steffen Leuthäusser, Lars H. Peeck, Herbert Plenio
Rok vydání:	2010
Předmět:	Stereochemistry Organic Chemistry Cationic polymerization chemistry.chemical_element Protonation ROMP Catalysis Ruthenium Inorganic Chemistry chemistry.chemical_compound chemistry Polymerization Polymer chemistry Moiety Physical and Theoretical Chemistry Norbornene
Zdroj:	Organometallics. 29:4339-4345
ISSN:	1520-6041 0276-7333
Popis:	Grubbs−Hoveyda and Grubbs III type complexes with ferrocenyl- or −NEt2-substituted NHC ligands were synthesized according to standard procedures. The electron donation of the NHC ligands in the respective ruthenium complexes can be modulated by oxidation of the ferrocenyl moiety or by protonation of the amino group. The neutral and the respective cationic (oxidized or protonated) ruthenium complexes were tested in the ROMP of norbornene. The change in the electron donation of the NHC ligands upon protonation leads to a significant change in the double-bond geometry (from E/Z ratio = 0.78 to E/Z = 1.04) and in the microstructure of the resulting polynorbornene. Consequently, addition of acid and protonation of the living catalyst attached to the polymer chain during the polymerization reaction allows fine-tuning the E/Z ratio of the resulting polynorbornene.
Databáze:	OpenAIRE
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