165848 20260119151008.0 doi 10.1021/acs.organomet.1c00453 sideral 127203 ART-2021-127203 eng Hermosilla P. Universidad de Zaragoza (orcid)0000-0003-2249-6054 Rh Complexes with Pincer Carbene CNC Lutidine-Based Ligands: Reactivity Studies toward H2 Addition 2021 Access copy available to the general public Unrestricted Lutidine-based NHCs pincer precursors CNCMe and CNCMes were combined with [Rh(acac)(nbd)] (acac = acetylacetonate; nbd = 2, 5-norbornadiene) in the presence of Cs2CO3 to yield complexes [(CNC)MeRh(nbd)]PF6 (3) and [(CNC)MesRh(NCMe)]PF6 (4), respectively. While in 3, the nbd diolefin remains coordinated, in 4, the voluminous mesityl ligands induce nbd decoordination, so acetonitrile stabilizes Rh(I) adduct 4, which in turn undergoes substitution reactions with a number of neutral ligands to produce cationic complexes [(CNC)MesRh(L)]PF6 (L = CO (5), PMe2Ph (6), PEt3 (7), C2H4 (8)). These complexes have been studied through VT NMR measurements and the molecular structures by X-ray crystallography in the case of adducts 4-7. Deprotonation reactions on cationic complexes 3-6 with hard bases yielded the corresponding neutral complexes [(CNC)*MeRh(nbd)] (9) and mesityl derivatives [(CNC)*MesRh(L)] (L = NCCH3 (10), CO (11), PMe2Ph (12)), all of which are dearomatized complexes due to the deprotonation of one of the methylene arms, a situation confirmed by the X-ray molecular structure of carbonyl adduct 5. We studied the reactivity toward dihydrogen with neutral adducts 11 and 12. The electron rich phosphane 12 adds H2 through oxidative addition, affording the bis(hydrido) Rh(III) complex [(CNC)*MesRh(PMe2Ph)H2] (14). However, the carbonyl adduct 11 reacts with H2 in a different way, so that the central pyridinic ring becomes hydrogenated, breaking the aromaticity and leading to complex [(CNC-H2)*MesRh(CO)] (13), isolated as a mixture of two isomers. DFT studies were carried out in order to establish the mechanisms followed on these hydrogenations, finding that, while the phosphane adduct reacts following an oxidative addition mechanism, the carbonyl complex follows a more complex base-induced profile due to the instability of hydride carbonyl species. © 2021 American Chemical Society. info:eu-repo/grantAgreement/ES/DGA-FSE/E42-20R info:eu-repo/grantAgreement/ES/MINECO-FEDER/PGC2018-099383-B-I00 info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 3.837 2021 CHEMISTRY, ORGANIC 15 / 56 = 0.268 2021 Q2 T1 CHEMISTRY, INORGANIC & NUCLEAR 12 / 46 = 0.261 2021 Q2 T1 0.994 2021 Organic Chemistry 2021 Q1 Inorganic Chemistry 2021 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion García-Orduña P. (orcid)0000-0002-7063-1292 Lahoz F.J. (orcid)0000-0001-8054-2237 Polo V. Universidad de Zaragoza (orcid)0000-0001-5823-7965 Casado M.A. Universidad de Zaragoza (orcid)0000-0003-1707-3022 2010 760 Universidad de Zaragoza Dpto. Química Inorgánica Área Química Inorgánica 2012 755 Universidad de Zaragoza Dpto. Química Física Área Química Física 40, 22 (2021), 3720-3732 Organometallics Organometallics 0276-7333 888503 http://zaguan.unizar.es/record/165848/files/texto_completo.pdf Postprint 3033000 http://zaguan.unizar.es/record/165848/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:165848 articulos driver 2026-01-19-15:09:29 ARTICLE