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Arene C−H Bond Activation and Arene Oxidative Coupling by Cationic Palladium(II) Complexes

Ackerman, Lily J. and Sadighi, Joseph P. and Kurtz, David M. and Labinger, Jay A. and Bercaw, John E. (2003) Arene C−H Bond Activation and Arene Oxidative Coupling by Cationic Palladium(II) Complexes. Organometallics, 22 (19). pp. 3884-3890. ISSN 0276-7333. https://resolver.caltech.edu/CaltechAUTHORS:20170310-073002998

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Abstract

N,N‘-Diaryl-α-diimine-ligated Pd(II) dimethyl complexes (^(tBu)2^(Ar)DAB^(Me))PdMe_2 and {(CF_3)_2^(Ar)DAB^(Me)}PdMe_2 {^(tBu)2^(Ar)DAB^(Me): ArNC═(CH_3)−C(CH_3═NAr, Ar=3,5-di-tert-butylphenyl; (CF_3)_2^(Ar)DAB^(Me):Ar = 3,5-bis(trifluoromethyl)phenyl} undergo protonolysis with HBF_4(aq) in trifluoroethanol (TFE) to form cationic complexes [(α-diimine)Pd(CH_3)(H_2O)][BF_4]. The cations activate benzene C−H bonds at room temperature. Kinetic analyses reveal trends similar to those observed for the analogous platinum complexes:  the C−H activation step is rate-determining (KIE = 4.1 ± 0.5) and is inhibited by H_2O. The kinetic data are consistent with a mechanism in which benzene substitution proceeds by a solvent- (TFE-) assisted associative pathway. Following benzene C−H activation under 1 atm O_2, the products of the reaction are biphenyl and a dimeric μ-hydroxide complex, [(α-diimine)Pd(OH)]_2[BF_4]_2. The Pd(0) formed in the reaction is reoxidized by O_2 to the dimeric μ-hydroxide complex after the oxidative C−C bond formation. The regioselectivity of arene coupling was investigated with toluene and α,α,α-trifluorotoluene as substrates.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/om0303294DOIArticle
http://pubs.acs.org/doi/full/10.1021/om0303294PublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/om0303294PublisherSupporting Information
ORCID:
AuthorORCID
Kurtz, David M.0000-0002-6382-4651
Labinger, Jay A.0000-0002-1942-9232
Additional Information:© 2003 American Chemical Society. Received 5 May 2003. Published online 14 August 2003. Published in print 1 September 2003. This work has been generously supported by BP. L.J.A. thanks the National Science Foundation for a Graduate Research Fellowship. J.P.S. thanks the National Institutes of Health for an NRSA Postdoctoral Fellowship. D.M.K. thanks the Caltech Student-Faculty Programs Office and Thomas and Ruth Hayes for a Summer Undergraduate Research Fellowship (SURF). We thank Dr. Michael W. Day and Lawrence M. Henling for crystallography assistance.
Funders:
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
NIH Postdoctoral FellowshipUNSPECIFIED
Caltech Student-Faculty Programs OfficeUNSPECIFIED
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
Issue or Number:19
Record Number:CaltechAUTHORS:20170310-073002998
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170310-073002998
Official Citation:Arene C−H Bond Activation and Arene Oxidative Coupling by Cationic Palladium(II) Complexes Lily J. Ackerman, Joseph P. Sadighi, David M. Kurtz, Jay A. Labinger, and John E. Bercaw Organometallics 2003 22 (19), 3884-3890 DOI: 10.1021/om0303294
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75014
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:10 Mar 2017 16:49
Last Modified:03 Oct 2019 16:45

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