View Item 

Ru-based olefin metathesis catalysts bearing ph-responsive n-heterocyclic carbene (NHC) ligands: Activity control via degree of protonation

Access Status
Fulltext not available
Authors
Balof, S.
Yu, B.
Lowe, Andrew
Ling, Y.
Zhang, Y.
Schanz, H.
Date
2009
Type
Journal Article

Metadata
Show full item record
Citation
Balof, S. and Yu, B. and Lowe, A. and Ling, Y. and Zhang, Y. and Schanz, H. 2009. Ru-based olefin metathesis catalysts bearing ph-responsive n-heterocyclic carbene (NHC) ligands: Activity control via degree of protonation. European Journal of Inorganic Chemistry (13 SPEC. ISS.): pp. 1717-1722.
Source Title
European Journal of Inorganic Chemistry
DOI
ISSN
School
Nanochemistry Research Institute
URI
Collection
Abstract

Olefin metathesis catalysts (H2ITap)(PCy3)Cl2Ru=CHPh (4)and (H2ITap)Cl2Ru=CH-(C6H4-O-iPr) (5)[H2ITap = 1,3-bis-(2-,6-dimethyl-4- dimethylaminophenyl)-4,5-dihydroimid-azol-2-ylidene] were used for the ring-opening metathesispolymerization (ROMP) of exo-7-oxanorbornene derivative 7in the presence of various amounts of acid. Upon gradualprotonation of the NMe2 groups of the H2Tap ligand, the me-tathesis activity of both catalysts were gradually reduced dueto electronic changes of the N-heterocyclic carbene (NHC)ligand donor capability. The investigation of the ROMP poly-mer 8, DFT calculations and measurements of the initiationkinetics prove that the reduced activity is solely due to re-duced rates of propagation. © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009.