RT info:eu-repo/semantics/article
T1 Versatile Rh- and Ir-Based Catalysts for CO2Hydrogenation, Formic Acid Dehydrogenation, and Transfer Hydrogenation of Quinolines
A1 Fidalgo Zorrilla, Jairo
A1 Ruiz Castañeda, Margarita
A1 García Herbosa, Gabriel
A1 Carbayo Martín, Mª Aránzazu
A1 Jalón, Félix A.
A1 Rodríguez, Ana M.
A1 Manzano, Blanca R.
A1 Espino Ordóñez, Gustavo
K1 Química inorgánica
K1 Chemistry, Inorganic
AB Considering the interest in processes related to hydrogen storage such as CO2 hydrogenation and formic acid (FA) decomposition, we have synthesized a set of Ir, Rh, or Ru complexes to be tested as versatile precatalysts in these reactions. In relation with the formation of H2 from FA, the possible applicability of these complexes in the transfer hydrogenation (TH) of challenging substrates as quinoline derivatives using FA/formate as hydrogen donor has also been addressed. Bearing in mind the importance of secondary coordination sphere interactions, N,N′ ligands containing NH2 groups, coordinated or not to the metal center, were used. The general formula of the new complexes are [(p-cymene)RuCl(N,N′)]X, X = Cl–, BF4– and [Cp*MCl(N,N′)]Cl, M = Rh, Ir, where the N,N′ ligands are 8-aminoquinoline (HL1), 6-pyridyl-2,4-diamine-1,3,5-triazine (L2) and 5-amino-1,10-phenanthroline (L3). Some complexes are not active or catalyze only one process. However, the complexes [Cp*MCl(HL1)]Cl with M = Rh, Ir are versatile catalysts that are active in hydrogenation of quinolines, FA decomposition, and also in CO2 hydrogenation with the iridium derivative being more active and robust. The CO2 hydrogenation takes place in mild conditions using only 5 bar of pressure of each gas (CO2 and H2). The behavior of some precatalysts in D2O and after the addition of 9 equiv of HCO2Na (pseudocatalytic conditions) has been studied in detail and mechanisms for the FA decomposition and the hydrogenation of CO2 have been proposed. For the Ru, Ir, or Rh complexes with ligand HL1, the amido species with the deprotonated ligand are observed. In the case of ruthenium, the formate complex is also detected. For the iridium derivative, both the amido intermediate and the hydrido species have been observed. This hydrido complex undergoes a process of umpolung D+↔ Ir–D. All in all, the results of this work reflect the active role of −NH2 in the transfer of H+.
PB ACS Publications
SN 0020-1669
YR 2018
FD 2018-11
LK http://hdl.handle.net/10259/8383
UL http://hdl.handle.net/10259/8383
LA eng
NO We gratefully acknowledge thefinancial support provided by the Spanish Ministerio de Economía y Competitividad - FEDER (CTQ2014-58812-C2-1-R). M. R.-C. is grateful for the grant from University of Castilla-La Mancha (programa propio).
DS Repositorio Institucional de la Universidad de Burgos
RD 23-nov-2024