Substrate-Mediated Deactivation of a Ru((P2N2Bn)-N-tBu) Cooperative Complex

作者：Bow John Paul J; Boyle Paul D; Blacquiere Johanna M

来源：European Journal of Inorganic Chemistry, 2015, 2015(25): 4162-4166.

DOI：10.1002/ejic.201500798

• Cooperative effects
• Homogeneous catalysis
• Ligand design
• Ruthenium
• Vinylidene ligands

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 (P2N2R)-N-R' (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)-((P2N2Bn)-N-tBu)(MeCN)][PF6] as the catalyst, no turnover was observed in the anti-Markovnikov hydration of alkynes, aknown PT MLC reaction. Treatment of the cooperative complex with phenylacetylene affords a vinylammonium product in which the pendant nitrogen atom of the (P2N2Bn)-N-tBu 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.

• 出版日期2015-9