Chemistry Publications

Title

Origin of Stability and Inhibition of Cooperative Alkyne Hydrofunctionalization Catalysts

Document Type

Article

Publication Date

7-5-2021

Journal

Chemistry Europe

URL with Digital Object Identifier

10.1002/cctc.202100622

Abstract

New entries to the [Ru(Cp/Cp*)(PR2NR′2)(MeCN)]PF6 catalyst family were synthesized, including a Cp complex (R = Cy; R′ = Ph) and two Cp* complexes (R = Cy, Ph; R′ = Ph). These and other derivatives were used for the intramolecular hydroamination of 2-ethynylaniline to elucidate trends in catalytic lifetime and rate. The readily accessible [Ru(Cp)(PCy2NPh2)(MeCN)]PF6 derivative showed comparable lifetime to [Ru(Cp)(Pt−Bu2NPh2)(MeCN)]PF6, the previous optimal catalyst. Donor-free ‘active’ catalysts, [Ru(Cp/Cp*)(PCy2NPh2)]PF6, were prepared and their thermal stability was assessed. The relatively high stability of the Cp derivative was explained by the capacity of the PCy2NPh2 ligand to coordinate in a κ3-(P,P,Ar) mode, which protects the low-coordinate species. This coordination mode is inaccessible with the Cp* derivative. Additionally, [Ru(Cp*)(PCy2NPh2)]PF6 readily activated the C−Cl bond of the solvent dichloromethane. Variable time normalization analysis (VTNA) revealed that the indole product inhibited the catalyst [Ru(Cp)(PCy2NPh2)(MeCN)]PF6, which slowed catalytic rates.

Citation of this paper:

Chapple, D.E., Boyle, P.D. and Blacquiere, J.M. (2021), Origin of Stability and Inhibition of Cooperative Alkyne Hydrofunctionalization Catalysts. ChemCatChem. https://doi.org/10.1002/cctc.202100622

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