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- Title
Nucleophilicity of Alkyl Zirconocene and Titanocene Precatalysts, and Kinetics of Activation by Carbenium Ions and by B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>.
- Authors
Berionni, Guillaume; Kurouchi, Hiroaki; EisENburger, LuciEN; Mayr, Herbert
- Abstract
Kinetics of activation of methyl and benzyl metallocene precatalysts by benzhydrylium ions, tritylium ions, and triarylborane B(C6F5)3 were measured spectrophotometrically. The rate constants correlate linearly with the electrophilicity parameter E of the benzhydrylium and tritylium ions employed, allowing us to determine the σ-nucleophilicities of the metal-carbon bond of several zirconocenes and titanocenes. Bridging, substitution, metal, and ligand effects on the rates of metal-alkyl bond cleavage (M=Zr, Ti) were studied and structure-reactivity correlations were used to predict the kinetics of generation of metallocenium ions pairs, which are active catalysts in polymerization reactions and are highly electrophilic Lewis acids in frustrated Lewis pair catalysis.
- Subjects
ANALYTICAL mechanics; LEWIS acids; POLYMERIZATION; CHEMICAL reactions; METALLOCENES
- Publication
Chemistry - A European Journal, 2016, Vol 22, Issue 32, p11196
- ISSN
0947-6539
- Publication type
Article
- DOI
10.1002/chem.201602452