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Chelating Base Effects in Palladium-Mediated Activation of Molecular Oxygen

Keith, Jason M. and Goddard, William A., III (2012) Chelating Base Effects in Palladium-Mediated Activation of Molecular Oxygen. Organometallics, 31 (2). pp. 545-552. ISSN 0276-7333. https://resolver.caltech.edu/CaltechAUTHORS:20120305-151126356

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Abstract

We elucidate here the mechanism for the reaction of molecular oxygen with palladium-hydride complexes in toluene using quantum mechanics (B3LYP/LACVP** with the PBF polarizable continuum solvent model) for ((−)sparteine)-PdII(H)OAc. Here we focus specifically on two classes of pathways: (1) those proceeding through Pd0 and (2) those involving direct insertion of oxygen into the Pd–H bond. In particular, we present calculated potential energy surfaces and structures of the ((−)-sparteine)PdH system in which the OAc ion is substituted for Cl. We find that the acetate ligand has the ability to act as a base while chelating the Pd, making an external base unnecessary and significantly lowering the energy barrier involved in the Pd^0 pathway. This switches the calculated preference to the reductive elimination pathway proceeding through Pd^0 (ΔΔH^(‡) = 1.0 kcal/mol, ΔΔG^(‡) = −7.7 kcal/mol). The results presented herein demonstrate the ability to steer the reaction pathway through the choice of ancillary ligands. We expect that this strategy might contribute significantly to the development of new catalytic systems utilizing molecular oxygen as the stoichiometric oxidant.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/om200809uDOIArticle
ORCID:
AuthorORCID
Keith, Jason M.0000-0002-5292-397X
Goddard, William A., III0000-0003-0097-5716
Additional Information:© 2012 American Chemical Society. Received: July 29, 2011; Published: January 11, 2012. This research was partly funded by the DOE (DE-AC02-06CH11357 and DE-FG01-04ER04-20), NSF (CTS-0608889 and CMMI-072870), and Chevron Corp. The facilities used were funded by grants from ARO-DURIP and ONR-DURIP.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-AC02-06CH11357
Department of Energy (DOE)DE-FG01-04ER04-20
NSFCTS-0608889
NSFCMMI-072870
Chevron CorpUNSPECIFIED
Issue or Number:2
Record Number:CaltechAUTHORS:20120305-151126356
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20120305-151126356
Official Citation:Chelating Base Effects in Palladium-Mediated Activation of Molecular Oxygen Jason M. Keith and William A. Goddard III Organometallics 2012 31 (2), 545-552
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:29578
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:13 Mar 2012 16:44
Last Modified:27 Feb 2020 23:59

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