Shvo-Type Metal–Ligand Cooperative Catalysts: Tethered η5‑Oxocyclohexadienyl Ruthenium Complexes

• Published in: Organometallics 2022-06, Vol.41 (11), p.1391-1402
• Main Authors: Puig, Emmanuel, Verron, Raphaël, Kechaou-Perrot, Manel, Vendier, Laure, Gornitzka, Heinz, Miqueu, Karinne, Sotiropoulos, Jean-Marc, Fischmeister, Cédric, Sutra, Pierre, Igau, Alain
• Format: Article
• Language: English
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/acs.organomet.2c00123

Diverse synthetic routes of tethered η5-oxocyclohexadienyl ruthenium complexes, which are the extended version of the η4-cyclopentadienone Shvo-type active catalyst, are described and their reactivity studies are reported. An original dimeric η5-oxocyclohexadienyl compound has been isolated and its solid-state structure was established by X-ray analysis. DFT computational data suggested that this dimeric compound is prone to generate a coordinatively unsaturated mononuclear Lewis acid metal complex bearing a Lewis basic π-coordinated η5-oxocyclohexadienyl ligand. Preliminary studies in (transfer)­hydrogenation of acetophenone confirmed that the dimeric η5-oxocyclohexadienyl complex behaves as a bifunctional catalyst with metal–ligand cooperativity. Promising results were obtained under base-free conditions using dihydrogen, iPrOH, and formic acid as hydrogen donors, the latter being active in water, hence highlighting the robustness and stability of the catalyst and opening perspectives toward sustainable catalytic transformations.