Effects of the halogenido ligands on the Kumada-coupling catalytic activity of [Ni{tBuN(PPh2)2-κ2P}X2], X = Cl, Br, I, complexes

Autor
Ioannou, Polydoros-Chrysovalantis
Kakridi, Kalliopi
Raptopoulou, Catherine P.
Psycharis, Vassilis
Kyritsis, Panayotis
Datum vydání
2022Publikováno v
RSC AdvancesRočník / Číslo vydání
12 (4)ISBN / ISSN
ISSN: 2046-2069Metadata
Zobrazit celý záznamKolekce
Tato publikace má vydavatelskou verzi s DOI 10.1039/d1ra04572e
Abstrakt
Novel nickel(II) complexes bearing (terc-butyl)bis(diphenylphosphanyl)amine and different halogenido ligands, [Ni(P,P)X2] = [Ni{tBuN(PPh2)2-κ(2)P}X2], (X = Cl, Br, I) are prepared, characterized by IR and NMR spectroscopy, mass spectrometry and X-ray crystallography, and tested as catalysts in the Kumada cross-coupling reaction of model substituted iodobenzenes and p-tolylmagnesium bromide. The data obtained together with DFT calculations indicate that these new catalysts operate in the Ni(I)-Ni(III) mode. The highest catalytic activity and selectivity are exhibited by [Ni(P,P)Cl2], which is most easily reduced by the used Grignard reagent to the Ni(I) state. This process is much more energy demanding in the case of the bromido and iodido complexes, causing the appearance of the induction period. [Ni(P,P)Cl2] is also very active in the cross-couplings of substrates with iodine atoms sterically shielded by ortho substituents. The data obtained are in good accordance with the described positive effect of the increased electron-releasing power of N-substituents R' on the overall catalytic performance of [Ni{R'N(PPh2)2-κ(2)P}X2] complexes.
Klíčová slova
selective ethylene trimerization, coordination chemistry, molecular calculations, nickel(II) complexes, grignard-reagents, Pd(II), polymerization, tetramerization, immobilization, monosulfide
Trvalý odkaz
https://hdl.handle.net/20.500.14178/1577Licence
Licence pro užití plného textu výsledku: Creative Commons Uveďte původ-Neužívejte dílo komerčně 3.0 Unported