Tickner, Ben.Whitwood, AdrianCondon, ClairePlatas-Iglesias, CarlosDuckett, Simon2026-09-162026-09-162024-10-25B. J. Tickner, A. C. Whitwood, C. Condon, C. Platas-Iglesias, S. B. Duckett, Eur. J. Inorg. Chem. 2024, 27, e202400397. https://doi.org/10.1002/ejic.2024003971434-19481099-0682https://hdl.handle.net/2183/49276[Abstract] Metal dihydride dihydrogen-derived intermediates can be short-lived and difficult to detect despite their ubiquitous role in chemical transformations such as hydrogenation. Here, highly reactive [Ir(H)3(η2-η2-COD)(IMes)] forms by trapping [Ir(H)2(η2-H2)(η2-η2-COD)(IMes)]X [X=Cl or MeO], resulting from reaction of the Ir(I) precatalyst [IrCl(η2-η2-COD)(IMes)] with a base and H2. This trihydride allows access to the unusual [Ir2(H)4(OMe)(IMes)2(pyridine)3]X, [Ir2(H)2(μ2-H)2(η2-η2-COD)(IMes)2], [Ir3(H)9(IMes)3], [Ir4(H)12(IMes)4] and [Ir2(H)4(μ2-H)2(IMes)2(pyridine)2]. A combination of 2D NMR, parahydrogen hyperpolarized NMR, MS, and XRD are used to characterise these reaction products and rationalise their formation via the moiety {Ir(H)3(IMes)}. Consequently, the results of these studies have implications for iridium-catalyzed polarization transfer from parahydrogen via the well-known precursor [IrCl(η2-η2-COD)(IMes)].engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/TrappingIridium ClustersSABREHyperpolarisationCatalysisjournal articleopen access10.1002/ejic.202400397