150373 20251017144634.0 doi 10.1021/acs.inorgchem.2c00617 sideral 129199 ART-2022-129199 eng Hermosilla, P. Universidad de Zaragoza (orcid)0000-0003-2249-6054 Nucleophilic Reactivity at a=CH Arm of a Lutidine-Based CNC/Rh System: Unusual Alkyne and CO2Activation; 35476902 2022 Access copy available to the general public Unrestricted Reaction of an amido pincer complex (CNC)*Rh(CO)] (1) (CNC* is the deprotonated form of CNC) with carbon dioxide gave a neutral complex (CNC-CO2)Mes*Rh(CO)] (2), which is the result of a C-C bond-forming reaction between the deprotonated arm of the CNC* ligand and CO2. The molecular structure of 2 showed a zwitterionic complex, where the CO2 moiety is covalently connected to the former =CH arm of the CNC* pincer ligand. The unusual structure of 1 allowed us to explore the reactivity of the CO2 moiety with selected primary amines RNH2 (benzylamine and ammonia), which afforded cationic complexes (CNC)MesRh(CO)]HRNC(O)O] (R = Bz (3), H (4)). Compounds 3 and 4 are the result of a C-N coupling between the incoming amine and the CO2 fragment covalently connected to the pincer ligand in 2, a process that involves protonation of the "CH-CO2"fragment in 2 from the respective amines. Once revealed the nucleophilic character of the =CH fragment in 1, we explored its reactivity with alkynes, a study that enlightened a novel reactivity trend in alkyne activation. Reaction of 1 with terminal alkynes RCCH (R = Ph, 2-py, 4-C6H4-CF3) yielded neutral complexes (CNC-CH=CHR)Mes*Rh(CO)] (R = Ph (5), 2-py (6), 4-C6H4-CF3 (7)) in good yields. Deuterium labeling experiments with PhCCD confirmed that complex 5 is the product of a formal insertion of the alkyne into the C(sp2)-H bond of the deprotonated arm in 1. This structural proposal was further confirmed by the X-ray molecular structure of phenyl complex 5, which showed the alkyne covalently linked to the pincer ligand. Besides, this novel transformation was analyzed by DFT methods and showed a metal-ligand cooperative mechanism, based on the initial electrophilic attack of the alkyne to the =CH arm of the CNCMes* ligand (making a new C-C bond) followed by the action of a protic base (HN(SiMe3)2), which is able to perform a proton rearrangement that leads to the final product 5. © 2022 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/ 4.6 2022 CHEMISTRY, INORGANIC & NUCLEAR 5 / 42 = 0.119 2022 Q1 T1 0.997 2022 Chemistry (miscellaneous) 2022 Q1 Physical and Theoretical Chemistry 2022 Q1 Inorganic Chemistry 2022 Q1 8.0 2022 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion García-Orduña, P. (orcid)0000-0002-7063-1292 Sanz Miguel, P. J. Universidad de Zaragoza (orcid)0000-0002-8220-6031 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 66, 18 (2022), 7120–7129 Inorg. chem. Inorganic Chemistry 0020-1669 856204 http://zaguan.unizar.es/record/150373/files/texto_completo.pdf Postprint 1732405 http://zaguan.unizar.es/record/150373/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:150373 articulos driver 2025-10-17-14:27:46 ARTICLE