Synthesis and Characterization of Chiral Bis(aminato)iridate(I) and Aminato-Bridged Iridium(I) Complexes

Abstract

The two dinuclear IrI complexes [Ir2(μ‐Cl)2 {(R)‐(S)‐PPF‐PPh2}2] (1; (R)‐(S)‐PPF‐PPh2=(S)‐1‐(diphenylphosphino)‐2‐[(R)‐1‐(diphenylphosphino)ethyl]ferrocene and [Ir2(μ‐Cl)2{(R)‐binap}2] (3; (R)‐binap=(R)‐[1,1′‐binaphthalene]‐2,2′‐diylbis[diphenylphosphine]) smoothly react with 4 equiv. of the lithium salt of aniline to afford the new bis(anilido)iridate(I) (=bis(benzenaminato)iridate(1‐)) complexes Li[Ir(NHPh)2{(R)‐(S)‐PPF‐PPh2}] (4) and Li[Ir(NHPh)2{(R)‐binap}] (5), respectively. The anionic complexes 4 and 5 react upon protonolysis to give the dinuclear aminato‐bridged derivatives [Ir2(μ‐NHPh)2{(R)‐(S)‐PPF‐PPh2}2] (6) and [Ir2(μ‐NHPh)2{(R)‐binap}2] (7), which were characterized by X‐ray crystallography. None of the new complexes 4 – 7 shows catalytic activity in the hydroamination of olefins.

On the Effect of Iodide and Acids in the Metolachlor Process

“…Migratory insertion of the C�N moiety with the Ir−H bond leads to the iridium-amido intermediate B, 17 which has been suggested by Fryzuk and colleagues to activate dihydrogen via heterolytic 1,2-addition. 16,18 The resulting intermediate C might then liberate the amine upon ligand exchange with an incoming substrate molecule and regenerate A.…”

“…A plausible hydrogenation cycle (Scheme ) starts with the coordination of imine 1 to a cationic iridium­(III)-hydride A . Migratory insertion of the CN moiety with the Ir–H bond leads to the iridium-amido intermediate B , which has been suggested by Fryzuk and colleagues to activate dihydrogen via heterolytic 1,2-addition. , The resulting intermediate C might then liberate the amine upon ligand exchange with an incoming substrate molecule and regenerate A . This catalytic cycle follows Osborn’s original proposal of an invariant iridium­(III) oxidation state …”

Synthesis of and Structural Insights into Contact Ion Pair and Solvent-Separated Ion Pair Diphenyliridate Complexes

“…In these reports, a contact ion pair (CIP) structure in which the Li cation contacts to the anionic moiety was proposed. The synthesis of diaryliridate complexes stabilized by C–N chelating ligands, electron-deficient perhaloganated aryl groups, , or sterically hindered mesityl groups has also been reported; however, the molecular structures of these complexes have not been clarified so far …”