Chemistry Publications
Document Type
Article
Publication Date
9-1-2015
Journal
European Journal of Inorganic Chemistry
Volume
2015
Issue
25
First Page
4162
Last Page
4166
URL with Digital Object Identifier
https://doi.org/10.1002/ejic.201500798
Abstract
Ligand design for metal-ligand cooperative (MLC) catalysis is inherently more complex than that for traditional non-cooperative ligands. The basicity, sterics and structure of the acid/base group in MLC proton-transfer (PT) complexes, for instance, undoubtedly influence catalyst performance. Herein, we evaluate the highly tunable PR2NR′2 (1,5-R′-3,7-R-1,5-diaza-3,7-diphosphacyclooctane) ligand family for the first time in an organic transformation. With [Ru(Cp)(PtBu2NBn2)(MeCN)][PF6] as the catalyst, no turnover was observed in the anti-Markovnikov hydration of alkynes, a known PT MLC reaction. Treatment of the cooperative complex with phenylacetylene affords a vinylammonium product in which the pendant nitrogen atom of the PtBu2NBn2 ligand forms a Lewis acid-base adduct with the alpha-carbon atom of the vinylidene intermediate. Characterization by X-ray crystallography and NMR spectroscopy conclusively assign this structure in both the solid and the solution state. The adduct formation is irreversible, and the adduct is characterized as a catalyst deactivation product. Snapping Shut: The PR2NR′2 ligand family (R and R′ are removed for clarity in the graphic) open the door for easily tuned catalysts for cooperative organic transformations. However, the ligand swings toward the vinylidene, forming a stable (and catalytically inactive) Lewis acid-base adduct. (□ = open coordination site)
Citation of this paper:
Bow, J.-P.J., Boyle, P.D. and Blacquiere, J.M. (2015), Substrate-Mediated Deactivation of a Ru(PtBu2NBn2) Cooperative Complex. Eur. J. Inorg. Chem., 2015: 4162-4166. https://doi.org/10.1002/ejic.201500798
