Catalytic systems based on nickel(ii) complexes with bis(3,5-dimethylpyrazol-1-yl)methane-impact of PPh3 on the formation of precatalysts and selective dimerization of ethylene

This study was aimed at elucidating the role of Ph3P in the formation of Ni(ii) complexes which are active in ethylene oligomerization. Two ionic Ni(ii) complexes bearing bis(3,5-dimethylpyrazol-1-yl)methane ligand [NiL2(CH3CN)2]2+[NiBr3(PPh3)]2- and [NiL2Br]+[NiBr3(PPh3)]- have been synthesized. The structures of these compounds have been confirmed by X-ray diffraction. Individual and in situ complexes with PPh3 are in equilibria between different forms in solution. These forms include the free complex and free PPh3, and molecular and ionic complexes with coordinated triphenylphosphine. All individual compounds were active in ethylene dimerization upon activation with Et2AlCl, producing a mixture of butenes with activities up to 960 kg mol[Ni]-1 h-1 atm-1 and high selectivity (up to 100% of butenes and up to 90.5% of butene-1). The catalytic influence of triphenylphosphine has been evaluated-it increases the activity of the system up to 1800 kg mol[Ni]-1 h-1 atm-1 when 2 mol. equiv. of additive has been applied and completely changes the selectivity of the process towards internal olefins. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Authors
Zubkevich S.V.1 , Tuskaev V.A.1, 2 , Gagieva S.C.1 , Pavlov A.A.2 , Khrustalev V.N. 3, 4 , Polyakova O.V.1 , Zarubin D.N.2 , Kurmaev D.A.1 , Kolosov N.A.1 , Bulychev B.M.1
Publisher
Royal Society of Chemistry
Number of issue
3
Language
English
Pages
981-993
Status
Published
Volume
44
Year
2020
Organizations
  • 1 Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 11, Moscow, 119991, Russian Federation
  • 2 A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova st., 28, Moscow, 119334, Russian Federation
  • 3 National Research Center, Kurchatov Institute, Acad. Kurchatov Sq., 1, Moscow, 123182, Russian Federation
  • 4 Peoples' Friendship University of Russia, RUDN University, Miklukho-Maklay St., 6, Moscow, 117198, Russian Federation
Keywords
alkene; bis(3,5 dimethylpyrazol 1 yl)methane; ethylene; methane; nickel complex; triphenylphosphine; unclassified drug; Article; catalysis; chemical structure; complex formation; dimerization; oligomerization; priority journal; synthesis; X ray diffraction
Date of creation
10.02.2020
Date of change
10.02.2020
Short link
https://repository.rudn.ru/en/records/article/record/56609/
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