Buil Juan, M LuisaCollado Martínez, AlbaGómez Gallego, María Del MarEsteruelas Rodrigo, Miguel ÁngelSierra Rodríguez, Miguel ÁngelOñate, EnriqueNicasio, Antonio2024-11-182024-11-182021-03-31Organometallics 2021, 40, 989−10030276-733310.1021/acs.organomet.1c00068https://hdl.handle.net/20.500.14352/110688Rhodium and iridium diolefin catalysts for the acceptorless and base-free dehydrogenation of secondary alcohols have been prepared, and their degradation has been investigated, during the study of the reactivity of the dimers [M(μ-Cl)(η4-C8H12)]2 (M = Rh (1), Ir (2)) and [M(μ-OH)(η4-C8H12)]2 (M =Rh (3), Ir (4)) with 1,3-bis(6′-methyl-2′-pyridylimino)isoindoline (HBMePHI). Complex 1 reacts with HBMePHI, in dichloromethane, to afford equilibrium mixtures of 1, the mononuclear derivative RhCl(η4-C8H12){κ1-Npy-(HBMePHI)} (5), and the binuclear species [RhCl(η4-C8H12)]2{μ-Npy,Npy-(HBMePHI)} (6). Under the same conditions, complex 2 affords the iridium counterparts IrCl(η4-C8H12){κ1-Npy-(HBMePHI)} (7) and [IrCl- (η4-C8H12)]2{μ-Npy,Npy-(HBMePHI)} (8). In contrast to chloride, one of the hydroxide groups of 3 and 4 promotes the deprotonation of HBMePHI to give [M(η4-C8H12)]2(μ-OH){μ-Npy,Niso-(BMePHI)} (M = Rh (9), Ir (10)), which are efficient precatalysts for the acceptorless and base-free dehydrogenation of secondary alcohols. In the presence of KOtBu, the [BMePHI]− ligand undergoes three different degradations: alcoholysis of an exocyclic isoindoline-N double bond, alcoholysis of a pyridyl-N bond, and opening of the five-membered ring of the isoindoline coreengAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/journal articlepubs.acs.orghttps://pubs.acs.org/doi/10.1021/acs.organomet.1c00068restricted access547Rhodium complexIridium complexCatalysisDehydrogenationQuímica orgánica (Química)2306 Química Orgánica