%0 Journal Article
%A Buil Juan, M Luisa
%A Collado Martínez, Alba
%A Gómez Gallego, María Del Mar
%A Esteruelas Rodrigo, Miguel Ángel
%A Sierra Rodríguez, Miguel Ángel
%A Oñate, Enrique
%A Nicasio, Antonio
%T Preparation and degradation of rhodium and iridium diolefin catalysts for the acceptorless and base-free dehydrogenation of secondary alcohols
%D 2021
%@ 0276-7333
%U https://hdl.handle.net/20.500.14352/110688
%X Rhodium 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 exocyclicisoindoline-N double bond, alcoholysis of a pyridyl-N bond, and opening of the five-membered ring of the isoindoline core
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