Rhodium Complexes in P-H Bond Activation Reactions.

Autor: Varela-Izquierdo V; Departamento de Química Inorgánica, Instituto de Síntesis QuímicayCatálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain., Geer AM; Department of Chemistry, University of Virginia, Charlottesville, Virginia, 22904, USA., de Bruin B; University of Amsterdam, Van 't Hoff Institute for Molecular Sciences, Science park 904, 1098 XH, Amsterdam, The Netherlands., López JA; Departamento de Química Inorgánica, Instituto de Síntesis QuímicayCatálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain., Ciriano MA; Departamento de Química Inorgánica, Instituto de Síntesis QuímicayCatálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain., Tejel C; Departamento de Química Inorgánica, Instituto de Síntesis QuímicayCatálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, 50009, Zaragoza, Spain.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2019 Dec 10; Vol. 25 (69), pp. 15915-15928. Date of Electronic Publication: 2019 Nov 08.
DOI: 10.1002/chem.201903981
Abstrakt: The feasibility of oxidative addition of the P-H bond of PHPh 2 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)(C 2 H 4 )(PHPh 2 )] (Tp= hydridotris(pyrazolyl)borate): i) clean and quantitative reactions to terminal hydrido-phosphanido complexes [RhTp(H)(PPh 2 )(L)] (L=PMe 3 , PMe 2 Ph and PHPh 2 ), ii) equilibria between Rh I and Rh III species: [RhTp(H)(PPh 2 )(L)]⇄[RhTp(PHPh 2 )(L)] (L=PMePh 2 , PPh 3 ) and iii) a simple ethylene replacement to give the rhodium(I) complexes [Rh(κ 2 -Tp)(L)(PHPh 2 )] (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)(η 1 -Et)(κ C,P -CH 2 CH 2 PPh 2 )] 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 OPHPh 2 to [Rh(Tp)(C 2 H 4 )(PHPh 2 )] gave the related hydride complex [RhTp(H)(PHPh 2 )(POPh 2 )], but ethyl complexes resulted from hydride insertion into the Rh-ethylene bond in the reaction with [Rh(Tp)(C 2 H 4 ) 2 ].
(© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
Externí odkaz:
Nepřihlášeným uživatelům se plný text nezobrazuje