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Formation of Trivalent Zirconocene Complexes from ansa-Zirconocene-Based Olefin-Polymerization Precatalysts: An EPR- and NMR-Spectroscopic Study

Lenton, Taylor N. and Bercaw, John E. and Panchenko, Valentina N. and Zakharov, Vladimir A. and Babushkin, Dmitrii E. and Soshnikov, Igor E. and Talsi, Evgenii P. and Brintzinger, Hans H. (2013) Formation of Trivalent Zirconocene Complexes from ansa-Zirconocene-Based Olefin-Polymerization Precatalysts: An EPR- and NMR-Spectroscopic Study. Journal of the American Chemical Society, 135 (29). pp. 10710-10719. ISSN 0002-7863. doi:10.1021/ja403170u. https://resolver.caltech.edu/CaltechAUTHORS:20131008-104804358

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Abstract

Reduction of Zr(IV) metallocenium cations with sodium amalgam (NaHg) produces EPR signals assignable to Zr(III) metallocene complexes. The chloro-bridged heterodinuclear ansa-zirconocenium cation [(SBI)Zr(μ-Cl)_2AlMe_2]^+ (SBI = rac-dimethylsilylbis(1-indenyl)), present in toluene solution as its B(C_6F_5)_4^– salt, thus gives rise to an EPR signal assignable to the complex (SBI)Zr^(III)(μ-Cl)_2AlMe_2, while (SBI)ZrIII-Me and (SBI)Zr^(III)(μ-H)_2Al^(i)Bu_2 are formed by reduction of [(SBI)Zr(μ-Me)_2AlMe_2]^+ B(C_6F_5)_4– and [(SBI)Zr(μ-H)_3(AliBu_2)_2]^+ B(C_6F_5)_4^–, respectively. These products can also be accessed, along with (SBI)ZrIII-iBu and [(SBI)ZrIII]^+ AlR_4^–, when (SBI)ZrMe_2 is allowed to react with HAl^(i)Bu_2, eliminating isobutane en route to the Zr(III) complex. Further studies concern interconversion reactions between these and other (SBI)Zr(III) complexes and reaction mechanisms involved in their formation.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/ja403170uDOIArticle
http://pubs.acs.org/doi/abs/10.1021/ja403170uPublisherArticle
ORCID:
AuthorORCID
Panchenko, Valentina N.0000-0003-3771-8019
Additional Information:© 2013 American Chemical Society. Received: March 29, 2013; Published: June 10, 2013. This research was supported by Deutsche Forschhungsgemeinschaft (Grant Me1388/9-1), by the Russian Foundation of Basic Research (Grant 10-03-91330) and by US DOE, Office of Basic Energy Sciences (Grant DE-FG03-85ER13431). We thank Prof. Jay A. Labinger (California Institute of Technology), Dr. Konstantin P. Bryliakov (Boreskov Institute of Catalysis,) and Prof. Heiko Möller (University of Konstanz) for helpful discussions; Anke Friemel, Evelyn Wuttke, Martin Spitzbarth (University of Konstanz), David VanderVelde, and Angelo DiBilio (California Institute of Technology) for help with the acquisition and analysis of NMR and EPR spectra; and Lawrence M. Henling and Thomas S. Teets for assistance with mounting crystals and solving cyrstal structures. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to the California Institute of Technology (CHE-0639094).
Funders:
Funding AgencyGrant Number
Deutsche Forschhungsgemeinschaft (DFG)Me1388/9-1
Russian Foundation of Basic Research10-03-91330
Department of Energy (DOE)DE-FG03-85ER13431
NSF CRIF:MU AwardCHE-0639094
Issue or Number:29
DOI:10.1021/ja403170u
Record Number:CaltechAUTHORS:20131008-104804358
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20131008-104804358
Official Citation:Formation of Trivalent Zirconocene Complexes from ansa-Zirconocene-Based Olefin-Polymerization Precatalysts: An EPR- and NMR-Spectroscopic Study Taylor N. Lenton, John E. Bercaw, Valentina N. Panchenko, Vladimir A. Zakharov, Dmitrii E. Babushkin, Igor E. Soshnikov, Evgenii P. Talsi, and Hans H. Brintzinger Journal of the American Chemical Society 2013 135 (29), 10710-10719
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41738
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:09 Oct 2013 18:42
Last Modified:10 Nov 2021 04:33

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