Karatas, Mert OlgunHinojosa, Diego R.Passarelli, VincenzoOro, Luis A.Perez-Torrente, Jesus J.Castarlenas, Ricardo2026-04-042026-04-0420251477-92261477-9234https://doi.org/10.1039/d5dt01516bhttps://hdl.handle.net/11616/109312A series of rhodium(i) complexes of formula Rh{kappa 2C,X-(IDippR)}(cod) and Rh{kappa 2C,X-(IDippR)}(CO)2 {IDippR = 1-(R)-3-(2,6-diisopropylphenyl)-imidazolin-2-carbene; X = N, O; R = (6-yl-2-pyridone), (CH2CH2NC( 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 O)Ph), (CH2CH2COO); (cod = 1,5-cyclooctadiene)} containing anionic-tethered NHC-functionalized ligands, including pyridonato, amidato or carboxylato groups at the N-wingtip, has been prepared and their application to alkyne homocoupling has been investigated. The chelate coordination of the NHC-functionalized ligand generates 5, 6 and 7-membered metallacycles for pyridonato, amidato and carboxylato substituents, respectively. Preparation of the mixed bis-NHC derivative Rh{kappa 2C,O-(IDippCarbx)}(CO)(IPr) {IPr = 1,3-bis-(2,6-diisopropylphenyl)-imidazolin-2-carbene} is possible due to lability of one of the CO ligands in the bis-CO precursor. Reversible protonation is observed for pyridonato and carboxylato moieties but not for amidato counterpart. Alkyne dimerization catalytic activity is reported for N-based anionic groups whereas carboxylato counterparts are inefficient. A proton transfer mechanism is invoked for the gem-selectivity observed for cod-based catalysts whereas alkyne insertion is the regioselectivity-determining step for CO-containing analogues.eninfo:eu-repo/semantics/closedAccessTo-Tail DimerizationTerminal AlkynesMetal-ComplexesNhc LigandsCatalystsIridiumBondReactivityCarbopalladationHydrogenationArticle544015306153194099418610.1039/d5dt01516b2-s2.0-105018683319Q2WOS:001578191900001Q10000-0002-1735-64390000-0002-4849-20620000-0003-4460-86780000-0002-3327-09180000-0001-8500-2088