Journal article
Computational study of a new Heck reaction mechanism catalyzed by palladium(II/IV) species
Chemistry-A European Journal, Vol.7(8), pp.1703-1711
Apr/2001
Abstract
In this theoretical study on the Heck reaction we explore the feasibility of an alternative pathway that involves a Pd(II)/Pd(IV) redox system. Usually, the catalytic cycle is formulated based on a Pd(0)/Pd(II) mechanism, We performed quantum chemical calculations using density functional theory on a model system that consisted of diphosphinoethane (DPE) as a bidentate ligand and the substrates ethylene and phenyl iodide to compare both mechanisms. Accordingly, the Pd(II)/Pd(IV) mechanism is most likely to occur in the equatorial plane of an octahedral Pd(IV) complex. The energy profiles of both reaction pathways under consideration are largely parallel. A major difference is found for the oxidative addition of the C-I bond to the palladium centre,This is a rate-determining step of the Pd(II)/Pd(IV) mechanism, while it is facile for a Pd(0) catalyst. The calculations show that intermediate ligand detachment and reattachment is necessary in the course of the oxidative addition to Pd(II). Therefore, we expect the Pd(II)/Pd(IV) mechanism to be only feasible if a weakly coordinating ligand is present.
Details
- Title
- Computational study of a new Heck reaction mechanism catalyzed by palladium(II/IV) species
- Creators
- Andreas Sundermann (null) - The Weizmann Institute of ScienceOlivier Uzan (null) - The Weizmann Institute of ScienceJML Martin (null) - The Weizmann Institute of Science
- Resource Type
- Journal article
- Publication Details
- Chemistry-A European Journal, Vol.7(8), pp.1703-1711; Apr/2001
- Number of pages
- 9
- Language
- English
- DOI
- https://doi.org/10.1002/1521-3765(20010417)7:8<1703::AID-CHEM17030>3.0.CO;2-K
- Grant note
- J.M. is a Yigal Allon Fellow and the incumbent of the Helen and Milton A. Kimmelman Career Development Chair. A.S. gratefully acknowledges a postdoctoral fellowship of the MINERVA Foundation, Munich, Germany. O.U. is a doctoral fellow of the Feinberg Graduate School, Weizmann Institute of Science. This research was supported by the MINERVA foundation, Munich (Germany), and by the Tashtiyot program of the Ministry of Science (Israel). The Compaq ES40 server computer was jointly financed by the last two programs. The authors would like to thank Prof. David Milstein (Weizmann Institute) for helpful discussions and critical reading of the manuscript prior to submission, and Prof. Manfred Reetz (Max-Planck Institut für Kohlenforschung, Mülheim, Germany) for his encouragement
- Record Identifier
- 993264433103596
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