biostudies-literatureRuamps MIR RENARD3776https://www.ebi.ac.uk/biostudies/studies/S-EPMC9227367biostudies-literatureUnknown27(12)The coordination chemistry of the N-heterocyclic carbene ligand IMes^(NMe2)2, derived from the well-known IMes ligand by substitution of the carbenic heterocycle with two dimethylamino groups, was investigated with d⁶ [Mn(I), Fe(II)], d⁸ [Rh(I)], and d¹⁰ [Cu(I)] transition-metal centers. The redox behavior of the resulting organometallic complexes was studied through a combined experimental/theoretical study, involving electrochemistry, EPR spectroscopy, and DFT calculations. While the complexes [CuCl(IMes^(NMe2)2)], [RhCl(COD)(IMes^(NMe2)2)], and [FeCp(CO)₂ (IMes^(NMe2)2)](BF₄) exhibit two oxidation waves, the first oxidation wave is fully reversible but only for the first complex the second oxidation wave is reversible. The mono-oxidation event for these complexes occurs on the NHC ligand, with a spin density mainly located on the diaminoethylene NHC-backbone, and has a dramatic effect on the donating properties of the NHC ligand. Conversely, as the Mn(I) center in the complex [MnCp(CO)₂ ((IMes^(NMe2)2)] is easily oxidizable, the latter complex is first oxidized on the metal center to form the corresponding cationic Mn(II) complex, and the NHC ligand is oxidized in a second reversible oxidation wave.Molecules (Basel, Switzerland)Redox-Switchable Behavior of Transition-Metal Complexes Supported by Amino-Decorated N-Heterocyclic Carbenes.PMC9227367IR-RPE CNRS 3443Vendier LLugan NSournia-Saquet ABastin SValyaev DACesar VRuamps MMouesca JMMaurel VRechignat LfalseRedox-Switchable Behavior of Transition-Metal Complexes Supported by Amino-Decorated N-Heterocyclic Carbenes.The coordination chemistry of the N-heterocyclic carbene ligand IMes^(NMe2)2, derived from the well-known IMes ligand by substitution of the carbenic heterocycle with two dimethylamino groups, was investigated with d⁶ [Mn(I), Fe(II)], d⁸ [Rh(I)], and d¹⁰ [Cu(I)] transition-metal centers. The redox behavior of the resulting organometallic complexes was studied through a combined experimental/theoretical study, involving electrochemistry, EPR spectroscopy, and DFT calculations. While the complexes [CuCl(IMes^(NMe2)2)], [RhCl(COD)(IMes^(NMe2)2)], and [FeCp(CO)₂ (IMes^(NMe2)2)](BF₄) exhibit two oxidation waves, the first oxidation wave is fully reversible but only for the first complex the second oxidation wave is reversible. The mono-oxidation event for these complexes occurs on the NHC ligand, with a spin density mainly located on the diaminoethylene NHC-backbone, and has a dramatic effect on the donating properties of the NHC ligand. Conversely, as the Mn(I) center in the complex [MnCp(CO)₂ ((IMes^(NMe2)2)] is easily oxidizable, the latter complex is first oxidized on the metal center to form the corresponding cationic Mn(II) complex, and the NHC ligand is oxidized in a second reversible oxidation wave.2022-01-01T00:00:00Z2022 Jun2025-04-21T14:18:01.947Z2025-04-21T14:18:01.947ZS-EPMC92273673574490310.3390/molecules27123776