CaltechAUTHORS
  A Caltech Library Service

Mechanistic Investigation of Iridium-Catalyzed Hydrovinylation of Olefins

Oxgaard, Jonas and Bhalla, Gaurav and Periana, Roy A. and Goddard, William A., III (2006) Mechanistic Investigation of Iridium-Catalyzed Hydrovinylation of Olefins. Organometallics, 25 (7). pp. 1618-1625. ISSN 0276-7333. https://resolver.caltech.edu/CaltechAUTHORS:20170725-150701455

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20170725-150701455

Abstract

C_2H_3-Ir(III)(acac-O,O)2(Py) dimerizes olefins through a C−H activation mechanism. The starting catalyst first isomerizes to the cis conformer through a dissociative process, where pyridine is lost, and then adds the olefin substrate to the cis conformer. [1,2]-Insertion of the vinyl moiety into the coordinating olefin generates a Ir−CH_2−CH_2−CH ═ CH_2 complex, which then isomerizes to an Ir(η^3-allyl) complex through a series of β-hydride transfer reactions. The η^3-allyl complex is significantly more stable than any other part of the surface and is expected to be the resting state of the catalyst. Addition of a second olefin to the η^3-allyl complex leads to an Ir−(CH_2−CH ═ CH−CH_3) complex with a coordinating olefin, which can transfer a hydrogen to the product, 2-butene, via a C−H activation transition state. This transition step is the rate-determining step, with a calculated ΔH^⧧ = 31.6 kcal/mol and ΔG^⧧ = 32.1 kcal/mol. Other pathways were found to have reasonable barriers, but are not competitive due to very facile barriers leading to the η^3-allyl complex. From the allyl complex, neither 1-butene or butadiene are feasible products. The presence of 1-butene in the product mixture is attributed to isomerization of 2-butene; that is, it is not a kinetic product.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/om050890xDOIArticle
http://pubs.acs.org/doi/abs/10.1021/om050890xPublisherArticle
ORCID:
AuthorORCID
Periana, Roy A.0000-0001-7838-257X
Goddard, William A., III0000-0003-0097-5716
Additional Information:© 2006 American Chemical Society. Received 16 October 2005. Published online 24 February 2006. Published in print 1 March 2006. The authors thank the National Science Foundation (CHE-0328121) and Chevron-Texaco Energy Research & Technology Company for financial support for this research. We also thank Dr. Robert Nielsen and Mr. John A Keith for valuable discussions regarding thermodynamics in solution.
Funders:
Funding AgencyGrant Number
NSFCHE-0328121
Chevron Texaco Energy Research and Technology Co.UNSPECIFIED
Issue or Number:7
Record Number:CaltechAUTHORS:20170725-150701455
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170725-150701455
Official Citation:Mechanistic Investigation of Iridium-Catalyzed Hydrovinylation of Olefins Jonas Oxgaard, Gaurav Bhalla, Roy A. Periana, and William A. Goddard, III Organometallics 2006 25 (7), 1618-1625 DOI: 10.1021/om050890x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:79353
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:25 Jul 2017 22:26
Last Modified:03 Oct 2019 18:19

Repository Staff Only: item control page