118184 20240319081018.0 doi 10.1021/acs.organomet.2c00125 sideral 129571 ART-2022-129571 eng González-Lainez, Miguel (orcid)0000-0001-7341-0033 N-Methylation of Amines with Methanol Catalyzed by Iridium(I) Complexes Bearing an N, O-Functionalized NHC Ligand 2022 Access copy available to the general public Unrestricted A set of neutral IrBr(L-2)-(kappa C-(t)BuImCH(2)PyCH(2)OMe)] and cationic Ir(L-2)-(kappa C, N-tBuImCH(2)PyCH(2)OMe)]PF6 (L-2 = cod, (CO)(2)) Ir(I) compounds featuring a flexible lutidine-derived polydentate ligand having NHC and - OMe as donor functions have been evaluated as catalyst precursors for the N-methylation of aniline using methanol both as a reducing agent and a C1 source. The carbonyl complexes are somewhat more active than the related diene compounds with the neutral compound IrBr(CO)(2)(kappa C-(t)BuImCH(2)PyCH(2)OMe)] being the more active. A range of aromatic primary amines, including heterocyclic amines, have been selectively transformed into the corresponding N-methylamino derivatives using this catalyst at a low catalyst loading (0.1 mol %) and substoichiometric amounts of Cs2CO3 (half equiv) as a base, in methanol at 423 K. For aliphatic primary amines, selective N, N-dimethylation was achieved under the same catalytic conditions. The unselective deprotonation of the methylene linkers in IrBr(CO)(2)(kappa C-(t)BuImCH(2)PyCH(2)OMe)] affords two isomeric neutral complexes featuring a coordinated dearomatized pyridine core, which were converted into Ir(OMe)(CO)(2)(kappa C-(t)BuImCH(2)PyCH(2)OMe)] upon addition of methanol. This compound undergoes thermal activation of a C-H bond of the tert-butyl group to give the cyclometalated iridium(I) complex Ir(CO)(2){kappa C-2, C-(-CH2Me2C-ImCH(2)PyCH(2)OMe)}] featuring a bidentate C, C-coordinated NHC ligand. Mechanistic investigations support a borrowing hydrogen mechanism proceeding through iridium(I) intermediates with the methoxo complex as the catalytic active species and the cyclometalated complex as the catalyst resting state. Deuterium labeling experiments have demonstrated that both species are in equilibrium under catalytic conditions, which is consistent with the exhibited catalytic activity of the cyclometalated complex. info:eu-repo/grantAgreement/ES/DGA-FSE/E42-20R info:eu-repo/grantAgreement/ES/MICINN-FEDER/PID2019-103965GB-I00 info:eu-repo/semantics/openAccess by http://creativecommons.org/licenses/by/3.0/es/ 2.8 2022 CHEMISTRY, ORGANIC 16 / 52 = 0.308 2022 Q2 T1 CHEMISTRY, INORGANIC & NUCLEAR 16 / 42 = 0.381 2022 Q2 T2 0.868 2022 Inorganic Chemistry 2022 Q1 Physical and Theoretical Chemistry 2022 Q1 Organic Chemistry 2022 Q1 6.6 2022 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Jiménez, M. Victoria (orcid)0000-0002-0545-9107 Azpiroz, Ramón (orcid)0000-0001-7904-2729 Passarelli, Vincenzo (orcid)0000-0002-1735-6439 Modrego, F. Javier Universidad de Zaragoza (orcid)0000-0002-9633-3285 Pérez-Torrente, Jesús J. Universidad de Zaragoza (orcid)0000-0002-3327-0918 2010 760 Universidad de Zaragoza Dpto. Química Inorgánica Área Química Inorgánica 41, 11 (2022), 1364–1380 Organometallics Organometallics 0276-7333 2897728 http://zaguan.unizar.es/record/118184/files/texto_completo.pdf Versión publicada 3009082 http://zaguan.unizar.es/record/118184/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:118184 articulos driver 2024-03-18-15:56:35 ARTICLE