Rhodium and Iridium Complexes of Lutidine-Based NHC/Amino Pincer Ligands: From Monodentate to Tetradentate Coordination Enabled by C–H Activation

摘要: A series of rhodium and iridium complexes derived from lutidine-based ligands (lutidine, 2,6-dimethylpyridine) with NHC and amino side-donor functions have been prepared and characterized. Deprotonation of the functionalized imidazolium salts, [tBuHImCH2PyCH2NR2]Br, by the bridging methoxo ligands of the dinuclear complexes [M(μ-OMe)(cod)]2 affords [MBr(cod)(κC-tBuImCH2PyCH2NR2)] (M = Rh and Ir) complexes from which a series of Rh(I) and Ir(I) complexes including [M(cod)(κ3C,N,N′-tBuImCH2PyCH2NR2)]+, [Rh(CO)(κ3C,N,N′-tBuImCH2PyCH2NR2)]+, and [IrBr(CO)2(κC-tBuImCH2PyCH2NR2)] are readily accessible by halide abstraction and/or carbonylation reactions. In contrast, direct metalation of imidazolium salts with the dinuclear compounds [M(μ-Cl)(cod)]2 (M = Rh and Ir) in the presence of potassium acetate and potassium iodide, a well-established synthetic route to M(III) species …