Strongly Polarized Iridiumδ−–Aluminumδ+ Pairs: Unconventional Reactivity Patterns Including CO2 Cooperative Reductive Cleavage

• DOI: 10.1021/jacs.1c01725
• Publication Date: 2021-03-18T21:23:46Z
• Authors: Léon Escomel; Iker Del Rosal; Laurent Maron; Erwann Jeanneau; Laurent Veyre; Chloé Thieuleux; Clément Camp
• Keywords: Reactivity; Decarbonylation; Reductive elimination; Bond cleavage; Cleavage (geology)

The iridium tetrahydride complex Cp*IrH4 reacts with a range of isobutylaluminum derivatives general formula Al(iBu)x(OAr)3–x (x = 1, 2) to give the unusual aluminum species [Cp*IrH3Al(iBu)(OAr)] (1) via reductive elimination route. Lewis acidity Al atom in 1 is confirmed by coordination pyridine, leading adduct [Cp*IrH3Al(iBu)(OAr)(Py)] (2). Spectroscopic, crystallographic, and computational data support description these heterobimetallic complexes 2 as featuring strongly polarized Al(III)δ+–Ir(III)δ− interactions. Reactivity studies demonstrate that binding base does not quench reactivity Ir–Al motif both promote cooperative cleavage heteroallenes. Specifically, promotes decarbonylation CO2 AdNCO, CO (trapped Cp*IrH2(CO)) alkylaluminum oxo ([(iBu)(OAr)Al(Py)]2(μ-O) (3)) ureate ({Al(OAr)(iBu)[κ2-(N,O)AdNC(O)NHAd]} (4)) species, respectively. bridged amidinate Cp*IrH2(μ-CyNC(H)NCy)Al(iBu)(OAr) (5) formed reaction dicyclohexylcarbodiimine. Mechanistic investigations DFT bond activation processes.