Mechanistic Insights on the β-(Z) alkyne hydrosilylation by a NHC-based Cp*Rh(III) catalyst: from catalyst design to an alternative model for H-Si activation

Poves-Ruiz, Isabel ; Sánchez-Page, Beatriz ; Jiménez, M. Victoria ; Gallegos, Miguel ; Munarriz, Julen (Universidad de Zaragoza) ; Passarelli, Vincenzo ; Pérez-Torrente, Jesús J. (Universidad de Zaragoza)

Resumen: In-depth studies on the residual hydrosilylation catalytic activity of samples of compound [Cp*RhI {(MeIm)2CH2}]+, bearing an unfunctionalized bis-NHC ligand, lead to the discovery of the excellent catalytic performance of the simple complex [Cp*RhI2(IMe)] (IMe = 1,3-dimethylimidozol-2-ylidene). This compound efficiently catalyzes the hydrosilylation of wide a range of terminal alkynes, with complete regio- and stereoselectivity toward the thermodynamically less stable β-(Z)-vinylsilane isomer. The reaction mechanism has been explored by DFT calculations. The reaction seems to proceed through an ionic outer-sphere mechanism, involving heterolytic activation of the hydrosilane assisted by the rhodium center and a solvent molecule (acetone). In the absence of acetone, a metal–ligand cooperation reaction pathway is proposed, in which the Cp* ligand acts as a proton-relay within the coordination sphere of the Rh(III) center. The cooperative activation of the hydrosilane by the metallocene moiety of the catalyst precursor generates a reactive Rh(I)–silyl intermediate bearing a pentamethylcyclopenta-1,3-diene ligand, [η4 -Cp*H], formed through protonation of the Cp* moiety.

Idioma: Inglés

DOI: 10.1016/j.jcat.2026.116721

Año: 2026

Publicado en: Journal of Catalysis 456 (2026), 116721 [13 pp.]
ISSN: 0021-9517

Financiación: info:eu-repo/grantAgreement/ES/DGA/E42-23R
Financiación: info:eu-repo/grantAgreement/ES/MCIU/PID2024-159030NA-I00
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2022-137208NB-I00

Tipo y forma: Article (Published version)

Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)
Área (Departamento): Área Química Física (Dpto. Química Física)