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Olefin Metathesis, p ‐Cresol, and the Second Generation Grubbs Catalyst: Fitting the Pieces
Author(s) -
Swart Marthinus R.,
Twigge Linette,
Erasmus Elizabeth,
Marais Charlene,
Bezuidenhoudt Barend C. B.
Publication year - 2021
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202100078
Subject(s) - chemistry , ruthenium , carbene , catalysis , metathesis , x ray photoelectron spectroscopy , medicinal chemistry , salt metathesis reaction , photochemistry , organic chemistry , polymerization , chemical engineering , engineering , polymer
p ‐Cresol as additive to the Grubbs second generation catalyst ( GII ) allows the cross‐metathesis of acrylates with prop‐1‐en‐1‐ylbenzenes under conditions that only give the prop‐1‐en‐1‐ylbenzene self‐metathesis product in the absence of cresol. NMR and IR spectroscopy, MALDI‐TOF MS and XPS supported the formation of a ruthenium benzylidene with hydrogen bonds between p ‐cresol and the chloride ligands of GII . XPS furthermore confirmed p ‐cresol to increase the binding energies of the GII Ru 3d 5/2 , 3d 3/2 , 3p 3/2 and 3p 1/2 photoelectron lines, whereas 1 H NMR spectroscopy indicated the carbene carbon and hydrogen to be shielded. It is thus postulated that p ‐cresol allows for more facile interaction between electron‐deficient compounds and the ruthenium benzylidene by decreasing the electron density on the metal center and increasing the electron density on the carbene.