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

0553702 - ÚMCH 2023 RIV GB eng J - Journal Article
Ioannou, P.-C. - Coufal, R. - Kakridi, K. - Raptopoulou, C. P. - Trhlíková, Olga - Psycharis, V. - Zedník, J. - Kyritsis, P. - Vohlídal, J.
Effects of the halogenido ligands on the Kumada-coupling catalytic activity of [Ni{tBuN(PPh2)2-.kappa.2P}X2], X = Cl, Br, I, complexes.
RSC Advances. Roč. 12, č. 4 (2022), s. 2227-2236. E-ISSN 2046-2069
Institutional support: RVO:61389013
Keywords : selective ethylene trimerization * coordination chemistry * molecular calculations
OECD category: Polymer science
Impact factor: 3.9, year: 2022
Method of publishing: Open access
https://pubs.rsc.org/en/content/articlelanding/2022/RA/D1RA04572E

Novel nickel(II) complexes bearing (tbutyl)bis(diphenylphosphanyl)amine and different halogenido ligands, [Ni(P,P)X2] = [Ni{tBuN(PPh2)2-κ2P}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-κ2P}X2] complexes.
Permanent Link: http://hdl.handle.net/11104/0328554