• Novel Mn(I) κ2-P,N triazole–phosphane complexes are introduced as rare earthabundant catalysts for dehydrogenaCve Si–O bond formaCon. • Catalyst performance is shown to be highly sensiCve to ligand hemilability, directly linking coordinaCon dynamics with acCvity and turnover. • In situ generaCon of a Mn(I) hydride species with LiHBEt3 triggers a divergent, highly efficient pathway, delivering turnover frequencies above 45,000 h⁻1 in hydrosilane methanolysis. • DFT studies support a concerted mechanism requiring triazole dissociaCon, providing a clear mechanisCc raConale for hemilability-controlled reacCvity. • Subtle electronic and steric ligand modificaCons lead to pronounced changes in coordinaCon dynamics and catalysis, providing design principles for earth-abundant Mn catalysts in sustainable Si–O bond formaCon and hydrogen generaCon. Manganese(I) complexes supported by hemilabile P-N ligands based on a 1,2,3-triazole scaffold have been synthesized and evaluated as catalysts for the dehydrogenative coupling of hydrosilanes with hydroxyl compounds. Structural and spectroscopic studies, including single-crystal X-ray diffraction, confirmed the bidentate coordination of these ligands in complexes 1 – 5 . Catalytic tests demonstrated that the ligand identity has a pronounced effect on the activity, with more labile triazole moieties showing superior performance. Notably, the use of LiHBEt 3 (1:1 M ratio with 1 ) enabled in situ generation of a manganese hydride species, significantly enhancing the reactivity in the methanolysis of hydrosilanes, where turnover frequencies above 45,000 h −1 were achieved. DFT calculations suggest that the reaction proceeds via a concerted pathway requiring triazole moiety dissociation, providing a mechanistic basis for the role of ligand hemilability in the activation of the hydrosilane.
García-Abellán et al. (Fri,) studied this question.