An insight into transfer hydrogenation reactions catalysed by iridium(iii) bis-n-heterocyclic carbenes

García, N. ; Jaseer, E.A. ; Munarriz, J. (Universidad de Zaragoza) ; Sanz Miguel, P.J. (Universidad de Zaragoza) ; Polo, V. (Universidad de Zaragoza) ; Iglesias, M. (Universidad de Zaragoza) ; Oro, L.A. (Universidad de Zaragoza)

Resumen: A variety of [M(L)2(L')2{kC,C'-bis(NHC)}]BF4 complexes (M = Rh or Ir; L = CH3CN or wingtip group; L' = I– or CF3COO–; NHC=N-heterocyclic carbene) have been tested as pre-catalysts for the transfer hydrogenation of ketones and imines. The conversions and TOF's obtained are closely related to the nature of the ligand system and metal centre, more strongly coordinating wingtip groups yielding more active and recyclable catalysts. Theoretical calculations at the DFT level support a classic stepwise metal-hydride pathway against the concerted Meerwein–Ponndorf–Verley (MPV) mechanism. The calculated catalytic cycle involves a series of ligand rearrangements due to the high trans effect of the carbene and hydrido ligands, which are more stable when situated in mutual cis positions. The reaction profiles obtained for the complexes featuring an iodide or a trifluoroacetate in one of the apical positions agree well with the relative activity observed for both catalysts.

Idioma: Inglés

DOI: 10.1002/ejic.201500853

Año: 2015

Publicado en: European Journal of Inorganic Chemistry 2015, 26 (2015), 4388-4395
ISSN: 1434-1948

Factor impacto JCR: 2.686 (2015)

Categ. JCR: CHEMISTRY, INORGANIC & NUCLEAR rank: 12 / 46 = 0.261 (2015) - Q2 - T1

Factor impacto SCIMAGO: 0.983 - Inorganic Chemistry (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E07
Financiación: info:eu-repo/grantAgreement/ES/MINECO/Consolider-Ingenio/CTQ2011-27593
Financiación: info:eu-repo/grantAgreement/ES/MINECO/Consolider-Ingenio/CTQ2012-35665
Financiación: info:eu-repo/grantAgreement/ES/MINECO/Consolider-Ingenio/CSD2009-0050

Tipo y forma: Article (PrePrint)

Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)
Área (Departamento): Área Química Física (Dpto. Química Física)