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oai:uvadoc.uva.es:10324/426652025-02-21T12:03:51Zcom_10324_28542com_10324_952com_10324_894col_10324_28543

E–Z Isomerization of Phosphine-Olefin (PEWO-F4) Ligands Revealed upon PdCl2 Capture: Facts and Mechanism Peñas de Frutos, Marconi Nicolás Vélez Blasco, Andrea Gioria, Estefania Espinet Rubio, Pablo Producción Científica The PEWO phosphines R2P(o-C6H4CH═CHC(O)Ph), R2P(o-C6H2F2CH═CHC(O)Ph), and R2P(o-C6F4CH═CHC(O)Ph) and their P-monodentate complexes trans-[PdCl2(P-monodentate)2] show, in solution and (when available) in the X-ray diffraction structures, an E configuration of the double bond. In contrast, the structures of [PdCl2(P-chelate)] display E and Z configurations. The E/Z isomerization of the latter requires first decoordination of the double bond, which then allows for easy rotation about the electron-deficient double bond. Thus, the E/Z equilibria exist for the free and the P-monodentate complexes as well but are not observed because they are extremely displaced toward the E isomer. Their capture in the form of [PdCl2(P-chelate)], with equilibrium constants on the order Keq ≈ 1–3, allows the two configurations to be observed and isolated. Evaluation of their ability to couple Pf–Pf from cis-[PdPf2(THF)2] (Pf = C6F5) affords values of their ΔG⧧(Pf–Pf)Pd parameters confirming that higher substitution of H by F produces lower coupling barriers and a double bond that is more electron deficient when it is free and more electron withdrawing when it is coordinated. 2020-09-30T08:57:11Z 2020-09-30T08:57:11Z 2019 info:eu-repo/semantics/article Organometallics, 2019, 38, 24, 4701–4707 0276-7333 http://uvadoc.uva.es/handle/10324/42665 10.1021/acs.organomet.9b00679 4701 24 4707 Organometallics 38 1520-6041 eng https://pubs.acs.org/doi/10.1021/acs.organomet.9b00679 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ © 2019 American Chemical Society Attribution-NonCommercial-NoDerivatives 4.0 Internacional American Chemical Society SI