127813 20241125101157.0 doi 10.1039/d3dt00744h sideral 133799 ART-2023-133799 eng Gómez-España, Alejandra Iridium-(K2-NSi) catalyzed dehydrogenation of formic acid: effect of auxiliary ligands on the catalytic performance 2023 Access copy available to the general public Unrestricted IThe iridium(III) complexes [Ir(H)(Cl)(κ2-NSitBu2)(κ2-bipyMe2)] (2) and [Ir(H)(OTf)(κ2-NSitBu2)(κ2-bipyMe2)] (3) (NSitBu2 = {4-methylpyridine-2-yloxy}ditertbutylsilyl) have been synthesized and characterized including X-ray studies of 3. A comparative study of the catalytic activity of complexes 2, 3, [Ir(H)(OTf)(κ2-NSitBu2)(coe)] (4), and [Ir(H)(OTf)(κ2-NSitBu2)(PCy3)] (5) (0.1 mol%) as catalysts precursors for the solventless formic acid dehydrogenation (FADH) in the presence of Et3N (40 mol%) at 353 K has been performed. The highest activity (TOF5 min ≈ 3260 h−1) has been obtained with 3 at 373 K. However, at that temperature the FTIR spectra show traces of CO together with the desired products (H2 and CO2). Thus, the best performance was achieved at 353 K (TOF5 min ≈ 1210 h−1 and no observable CO). Kinetic studies at variable temperature show that the activation energy of the 3-catalyzed FADH process is 16.76 kcal mol−1. Kinetic isotopic effect (5 min) values of 1.6, 4.5, and 4.2 were obtained for the 3-catalyzed dehydrogenation of HCOOD, DCOOH, and DCOOD, respectively, at 353 K. The strong KIE found for DCOOH and DCOOD evidenced that the hydride transfer from the C–H bond of formic acid to the metal is the rate-determining step of the process. info:eu-repo/grantAgreement/ES/DGA-FSE/E42-20R info:eu-repo/grantAgreement/ES/MICINN/PID2021-126212OB-I00 info:eu-repo/semantics/openAccess by http://creativecommons.org/licenses/by/3.0/es/ 3.5 2023 CHEMISTRY, INORGANIC & NUCLEAR 13 / 44 = 0.295 2023 Q2 T1 0.697 2023 Inorganic Chemistry 2023 Q1 6.6 2023 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion López-Morales, Jorge L. Español-Sanchez, Belinda García-Orduña, Pilar (orcid)0000-0002-7063-1292 Lahoz, Fernando J. Iglesias, Manuel (orcid)0000-0003-3144-5320 Fernández-Alvarez, Francisco J. Universidad de Zaragoza (orcid)0000-0002-0497-1969 2010 760 Universidad de Zaragoza Dpto. Química Inorgánica Área Química Inorgánica 52, 20 (2023), 6722-6729 Dalton Trans. Dalton Transactions 1477-9226 904069 http://zaguan.unizar.es/record/127813/files/texto_completo.pdf Versión publicada 2390607 http://zaguan.unizar.es/record/127813/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:127813 articulos driver 2024-11-22-12:09:54 ARTICLE