Resumen: We elucidate the mechanism of the manganese-catalyzed N-alkylation of aniline with benzyl alcohol mediated by a bis(1,2,3-triazolylidene) Mn(I) complex through a combination of experimental studies and density functional theory (DFT) calculations. Activation of the precatalyst by a base leads to the formation of an anionic alkoxo complex featuring a deprotonated methylene bridge, which is identified as the catalytically active species. Notably, the methylene linker exhibits previously unrecognized noninnocent behavior, undergoing reversible deprotonation and participating directly in proton-transfer steps of the catalytic cycle. Kinetic isotope effects and deuterium-labeling experiments support the involvement of both hydride transfer and alcohol-assisted proton processes in the rate-determining steps. These findings uncover a new mode of metal–ligand cooperation in triazolylidene-based manganese catalysts and provide mechanistic guidelines for the design of cooperative ligands in base-metal-borrowing hydrogen catalysis. Idioma: Inglés DOI: 10.1021/acs.inorgchem.6c01357 Año: 2026 Publicado en: Inorganic Chemistry 65, 16 (2026), 9265-9273 ISSN: 0020-1669 Financiación: info:eu-repo/grantAgreement/EC/H2020/101034288/EU/International Fellowship Programme for Talent Attraction to the Campus of International Excellence Campus Iberus/IberusExperience Tipo y forma: Artículo (Versión definitiva) Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)