Chirik, Paul J. and Day, Michael W. and Labinger, Jay A. and Bercaw, John E. (1999) Alkyl Rearrangement Processes in Organozirconium Complexes. Observation of Internal Alkyl Complexes during Hydrozirconation. Journal of the American Chemical Society, 121 (44). pp. 10308-10317. ISSN 0002-7863. doi:10.1021/ja9912022. https://resolver.caltech.edu/CaltechAUTHORS:20180413-134041553
Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20180413-134041553
Abstract
Isotopically labeled alkyl zirconocene complexes of the form (CpR_n)_2Zr(CH_2CDR‘_2)(X) (CpR_n = alkyl-substituted cyclopentadienyl; R‘ = H, alkyl group; X = H, D, Me) undergo isomerization of the alkyl ligand as well as exchange with free olefin in solution under ambient conditions. Increasing the substitution on the Cp ring results in slower isomerization reactions, but these steric effects are small. In contrast, changing X has a very large effect on the rate of isomerization. Pure σ-bonding ligands such as methyl and hydride promote rapid isomerization, whereas π-donor ligands inhibit β-H elimination and hence alkyl isomerization. For (η^5-C_5H_5)2Zr(R)(Cl), internal alkyl complexes have been observed for the first time. The rate of isomerization depends on the length of the alkyl group: longer alkyl chains (heptyl, hexyl) isomerize faster than shorter chains (butyl). The transient intermediate species have been identified by a combination of isotopic labeling and ^1H, ^2H, and ^(13)C NMR experiments. The solid-state structure of the zirconocene cyclopentyl chloride complex, Cp_2Zr(cyclo-C_5H_9)(Cl), has been determined by X-ray diffraction.
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Additional Information: | © 1999 American Chemical Society. ReceiVed April 15, 1999. This work has been supported by the U.S. DOE Office of Basic Energy Sciences (Grant No. DE-FG03-85ER13431) and Exxon Chemicals America. | |||||||||
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Issue or Number: | 44 | |||||||||
DOI: | 10.1021/ja9912022 | |||||||||
Record Number: | CaltechAUTHORS:20180413-134041553 | |||||||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20180413-134041553 | |||||||||
Official Citation: | Alkyl Rearrangement Processes in Organozirconium Complexes. Observation of Internal Alkyl Complexes during Hydrozirconation Paul J. Chirik, Michael W. Day, Jay A. Labinger, and John E. Bercaw Journal of the American Chemical Society 1999 121 (44), 10308-10317 DOI: 10.1021/ja9912022 | |||||||||
Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
ID Code: | 85841 | |||||||||
Collection: | CaltechAUTHORS | |||||||||
Deposited By: | George Porter | |||||||||
Deposited On: | 13 Apr 2018 20:51 | |||||||||
Last Modified: | 15 Nov 2021 20:32 |
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