Synthesis, Structure, and Activity of Enhanced Initiators for Olefin Metathesis
Abstract
A series of ruthenium olefin metathesis catalysts of the general structure (H_2IMes)(PR_3)(Cl)_2Ru CHPh (H_2IMes = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) have been prepared; these complexes are readily accessible in two steps from commercially available (H_2IMes)(PCy_3)(Cl)_2Ru CHPh. Their phosphine dissociation rate constants (k_1), relative rates of phosphine reassociation, and relative reaction rates in ring-opening metathesis polymerization (ROMP) and ring-closing metathesis (RCM) have been investigated. The rates of phosphine dissociation (initiation) from these complexes increase with decreasing phosphine donor strength. Complexes containing a triarylphosphine exhibit dramatically improved initiation relative to (H_2IMes)(PCy_3)(Cl)_2Ru CHPh. Conversely, phosphine reassociation shows no direct correlation with phosphine electronics. In general, increased phosphine dissociation leads to faster olefin metathesis reaction rates, which is of direct significance to both organic and polymer metathesis processes.
Additional Information
© 2003 American Chemical Society. Received June 26, 2002. Publication Date (Web): July 23, 2003. The authors would like to thank Lawrence M. Henling (X-ray crystallography), Tina M. Trnka, John P. Morgan, and D. William Ward for helpful discussions and Materia, Inc., for a generous supply of complex 2. J.A.L. thanks the National Institutes of Health for a postdoctoral fellowship. This work was supported by the National Science Foundation.Attached Files
Supplemental Material - ja027472tsi20030428_125525.pdf
Supplemental Material - ja027472tsi20030515_033334.cif
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Additional details
- Eprint ID
- 75740
- DOI
- 10.1021/ja027472t
- Resolver ID
- CaltechAUTHORS:20170405-140506647
- NIH Postdoctoral Fellowship
- NSF
- Created
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2017-04-05Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field