doi:10.1021/acscatal.1c00602engGaliana-Cameo M.Urriolabeitia A.Barrenas E.Passarelli V.Pérez-Torrente J.J.Di Giuseppe A.Polo V.Castarlenas R.Metal-Ligand Cooperative Proton Transfer as an Efficient Trigger for Rhodium-NHC-Pyridonato Catalyzed gem-Specific Alkyne DimerizationART-2021-126887The mononuclear square-planar Rh{¿2-X, N-(Xpy)}(¿2-coe)(IPr) (X = O, NH, NMe, S) complexes have been synthesized from the dinuclear precursor [Rh(µ-Cl)(IPr)( ¿2-coe)]2 and the corresponding 2-heteroatom-pyridinate salts. The Rh-NHC-pyridinato derivatives are highly efficient catalysts for gem-specific alkyne dimerization. Particularly, the chelating N, O-pyridonato complex displays turnover frequency levels of up 17 000 h-1 at room temperature. Mechanistic investigations and density functional theory calculations suggest a pyridonato-based metal-ligand cooperative proton transfer as responsible for the enhancement of catalytic activity. The initial deprotonation of a Rh-p-alkyne complex by the oxo-functionality of a ¿1-N-pyridonato moiety has been established to be the rate-limiting step, whereas the preferential protonation of the terminal position of a p-coordinated alkyne accounts for the exclusive observation of head-to-tail enynes. The catalytic cycle is closed by a very fast alkenyl-alkynyl reductive elimination. © 2021 American Chemical Society.2021http://zaguan.unizar.es/record/13144910.1021/acscatal.1c00602http://zaguan.unizar.es/record/131449oai:zaguan.unizar.es:131449info:eu-repo/grantAgreement/ES/DGA-FSE/E42-20Rinfo:eu-repo/grantAgreement/ES/MECD/FPU17-05417info:eu-repo/grantAgreement/ES/MICINN-FEDER/PID2019-103965GB-I00info:eu-repo/grantAgreement/ES/MICINN/PGC2018-099383-B-I00info:eu-repo/grantAgreement/ES/MINECO/IJCI-2015-27029ACS CATALYSIS 11, 12 (2021), 7553-7567byhttp://creativecommons.org/licenses/by/3.0/es/info:eu-repo/semantics/openAccess