64331 20230914083224.0 doi 10.1039/c6dt02571d sideral 102712 ART-2016-102712 eng Iturmendi, Amaia Universidad de Zaragoza N-Heterocyclic olefins as ancillary ligands in catalysis: A study of their behaviour in transfer hydrogenation reactions 2016 Access copy available to the general public Unrestricted The Ir(I) complexes [Ir(cod)(¿P,C,P'-NHOPPh2)]PF6 and [IrCl(cod)(¿C-NHOOMe)] (cod = 1,5-cyclooctadiene, NHOPPh2 = 1,3-bis(2-(diphenylphosphanyl)ethyl)-2-methyleneimidazoline) and NHOOMe = 1,3-bis(2-(methoxyethyl)-2-methyleneimidazoline), both featuring an N-heterocyclic olefin ligand (NHO), have been tested in the transfer hydrogenation reaction; this representing the first example of the use of NHOs as ancillary ligands in catalysis. The pre-catalyst [Ir(cod)(¿P,C,P'-NHOPPh2)]PF6 has shown excellent activities in the transfer hydrogenation of aldehydes, ketones and imines using iPrOH as a hydrogen source, while [IrCl(cod)(¿C-NHOOMe)] decomposes throughout the reaction to give low yields of the hydrogenated product. Addition of one or two equivalents of a phosphine ligand to the latter avoids catalyst decomposition and significantly improves the reaction yields. The reaction mechanism has been investigated by means of stoichiometric studies and theoretical calculations. The formation of the active species ([Ir(¿P,C,P'-NHOPPh2)(iPrO)]) has been proposed to occur via isopropoxide coordination and concomitant COD dissociation. Moreover, throughout the catalytic cycle the NHO moiety behaves as a hemilabile ligand, thus allowing the catalyst to adopt stable square planar geometries in the transition states, which reduces the energetic barrier of the process. info:eu-repo/grantAgreement/ES/DGA/E07 info:eu-repo/grantAgreement/ES/MEC/FPU14-06003 info:eu-repo/grantAgreement/ES/MINECO/Consolider-Ingenio/CSD2009-0050 info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 4.029 2016 CHEMISTRY, INORGANIC & NUCLEAR 7 / 46 = 0.152 2016 Q1 T1 1.229 2016 Inorganic Chemistry 2016 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion García, Nestor Jaseer, E.A Munárriz, Julen Universidad de Zaragoza (orcid)0000-0001-6089-6126 Sanz Miguel, Pablo J. Universidad de Zaragoza (orcid)0000-0002-8220-6031 Polo, Victor Universidad de Zaragoza (orcid)0000-0001-5823-7965 Iglesias, Manuel Universidad de Zaragoza (orcid)0000-0003-3144-5320 Oro, Luis A. Universidad de Zaragoza (orcid)0000-0001-7154-7239 2010 760 Universidad de Zaragoza Dpto. Química Inorgánica Área Química Inorgánica 2012 755 Universidad de Zaragoza Dpto. Química Física Área Química Física 2010 X Universidad de Zaragoza Dpto. Química Inorgánica Proy. investigación HWA 45, 32 (2016), 12835-12845 Dalton Trans. Dalton Transactions 1477-9226 783535 http://zaguan.unizar.es/record/64331/files/texto_completo.pdf Postprint 121013 http://zaguan.unizar.es/record/64331/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:64331 articulos driver 2023-09-13-10:42:45 ARTICLE