biostudies-literatureSilva-Munoz MMinisterio de Ciencia, Innovaci?n y Universidades25151-25160https://www.ebi.ac.uk/biostudies/studies/S-EPMC12754753biostudies-literatureUnknown64(51)We report the synthesis and characterization of rhodium and iridium complexes featuring a naphthalene-diimide (NDI)-functionalized N-heterocyclic carbene (NHC) ligand, in which the NDI unit is directly attached through an imide nitrogen. Electrochemical and spectroelectrochemical studies reveal that one- and two-electron reductions of the NDI moiety moderately enhance the electron-donating ability of the ligand, albeit to a lesser extent than in analogues where the NDI is fused to the carbene backbone. Catalytic investigations demonstrate that the iridium complexes efficiently promote the <i>N</i>-methylation of anilines with methanol via a borrowing-hydrogen pathway, outperforming the rhodium analogue. One-electron reduction of the NDI-NHC ligand leads to reversible deactivation of the catalyst, providing direct evidence for redox-switchable control of catalytic activity. Kinetic analyses and substrate studies indicate that imine reduction, rather than methanol dehydrogenation, constitutes the rate-determining step. These findings highlight NDI-NHC ligands as versatile redox-responsive platforms for fine-tuning electronic properties and catalytic performance in hydrgen-borrowing transformations.Inorganic chemistryRedox-Switchable Naphthalenediimide-NHC Iridium Complexes for Switchable Catalysis in Aniline Methylation with Methanol.PMC12754753PID2024-158991NB-I00TED2021-130647B-I00Martinez-Agramunt VPoyatos MSilva-Munoz MPeris EfalseRedox-Switchable Naphthalenediimide-NHC Iridium Complexes for Switchable Catalysis in Aniline Methylation with Methanol.We report the synthesis and characterization of rhodium and iridium complexes featuring a naphthalene-diimide (NDI)-functionalized N-heterocyclic carbene (NHC) ligand, in which the NDI unit is directly attached through an imide nitrogen. Electrochemical and spectroelectrochemical studies reveal that one- and two-electron reductions of the NDI moiety moderately enhance the electron-donating ability of the ligand, albeit to a lesser extent than in analogues where the NDI is fused to the carbene backbone. Catalytic investigations demonstrate that the iridium complexes efficiently promote the <i>N</i>-methylation of anilines with methanol via a borrowing-hydrogen pathway, outperforming the rhodium analogue. One-electron reduction of the NDI-NHC ligand leads to reversible deactivation of the catalyst, providing direct evidence for redox-switchable control of catalytic activity. Kinetic analyses and substrate studies indicate that imine reduction, rather than methanol dehydrogenation, constitutes the rate-determining step. These findings highlight NDI-NHC ligands as versatile redox-responsive platforms for fine-tuning electronic properties and catalytic performance in hydrgen-borrowing transformations.2025-01-01T00:00:00Z2025 Dec2026-06-06T08:18:14.097Z2026-05-27T03:11:52.571ZS-EPMC127547534138137510.1021/acs.inorgchem.5c04216