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Substrate‐Mediated Deactivation of a Ru(P t Bu 2 N Bn 2 ) Cooperative Complex
Author(s) -
Bow JohnPaul J.,
Boyle Paul D.,
Blacquiere Johanna M.
Publication year - 2015
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201500798
Subject(s) - chemistry , adduct , phenylacetylene , ligand (biochemistry) , catalysis , steric effects , stereochemistry , medicinal chemistry , nuclear magnetic resonance spectroscopy , crystallography , organic chemistry , biochemistry , receptor
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 P R 2 N R′ 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)(P t Bu 2 N Bn 2 )(MeCN)][PF 6 ] 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 P t Bu 2 N Bn 2 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.