Rhodium Complexes in P−H Bond Activation Reactions

Autor: Miguel A. Ciriano, José A. López, Ana M. Geer, Bas de Bruin, Victor Varela-Izquierdo, Cristina Tejel
Přispěvatelé: Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), European Commission, Ministerio de Economía y Competitividad (España), Netherlands Organization for Scientific Research, Gobierno de Aragón, Homogeneous and Supramolecular Catalysis (HIMS, FNWI)
Rok vydání: 2019
Předmět:
Zdroj: Digital.CSIC. Repositorio Institucional del CSIC
instname
Chemistry-A European Journal, 25(69), 15915-15928. Wiley-VCH Verlag
ISSN: 0947-6539
Popis: The feasibility of oxidative addition of the P−H bond of PHPh2 to a series of rhodium complexes to give mononuclear hydrido‐phosphanido complexes has been analyzed. Three main scenarios have been found depending on the nature of the L ligand added to [Rh(Tp)(C2H4)(PHPh2)] (Tp= hydridotris(pyrazolyl)borate): i) clean and quantitative reactions to terminal hydrido‐phosphanido complexes [RhTp(H)(PPh2)(L)] (L=PMe3, PMe2Ph and PHPh2), ii) equilibria between RhI and RhIII species: [RhTp(H)(PPh2)(L)]⇄[RhTp(PHPh2)(L)] (L=PMePh2, PPh3) and iii) a simple ethylene replacement to give the rhodium(I) complexes [Rh(κ2‐Tp)(L)(PHPh2)] (L=NHCs‐type ligands). The position of the P−H oxidative addition–reductive elimination equilibrium is mainly determined by sterics influencing the entropy contribution of the reaction. When ethylene was used as a ligand, the unique rhodaphosphacyclobutane complex [Rh(Tp)(η1‐Et)(κC,P‐CH2CH2PPh2)] was obtained. DFT calculations revealed that the reaction proceeds through the rate limiting oxidative addition of the P−H bond, followed by a low‐barrier sequence of reaction steps involving ethylene insertion into the Rh−H and Rh−P bonds. In addition, oxidative addition of the P−H bond in OPHPh2 to [Rh(Tp)(C2H4)(PHPh2)] gave the related hydride complex [RhTp(H)(PHPh2)(POPh2)], but ethyl complexes resulted from hydride insertion into the Rh−ethylene bond in the reaction with [Rh(Tp)(C2H4)2].
The generous financial support from AEI/FEDER, UE (CTQ2017‐83421‐P, C.T.), Gobierno de Aragón/FEDER (GA/FEDER, Inorganic Molecular Architecture Group E08_17R; C.T.) and the Netherlands Organization for Scientific Research (NWO) (TOP Grant 716.015.001, B.dB) is gratefully acknowledged. V.V. thanks MINECO/FEDER for an FPI fellowship.
Databáze: OpenAIRE
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