Influence of alcohols on the formation of the nickel complexes active in ethene oligomerization in the catalytic system Ni(PPh3)4/BF3·OEt2

Syntheses and properties of molecular nickel(II) hydride, methyl, and nickel(I) complexes supported by trimethylphosphane and (2-diphenylphosphanyl)thiophenolato and -naphtholato ligands

“…These assumptions are based on the classic works of Tolman [16,17] and others concerned with NMR identification of Ni(II) hydride model complexes [3][4][5][6]. On the other hand, according to the EPR data, the process of formation of the nickel complex catalysts includes the generation and stabilization of Ni(I) complexes, independent of the metal valence state in the initial compound [8][9][10][11][12].…”

“…Besides, there is an interesting and insufficiently explored question on the possible formation of nickel(I) complexes in the systems with chelating ligands. This question is topical since nickel(I) species are supposed to be involved in catalytic olefin oligomerisation reactions [10][11][12]. The system under investigation is shown to contain several molecular Ni(I) compounds.…”

Nickel Catalyzed Olefin Oligomerization and Dimerization

“…as the counter-ion is formed and proposed to be the relevant active catalyst. 425 Additionally, alcohols are presented by Saraev et al as promoters of such Ni(0) systems, 426 making possible the generation of an active Ni(II) hydride and/or a coordinatively unsaturated cationic Ni(I) species, described as being ten times more active catalysts than the Ni(II) hydride. 427 Based on a 429 Increase of Brønsted acid content and its effect over time, from the reaction of BF 3 .Et 2 O with water (as a solvent impurity), was demonstrated in a more detailed study.…”

“…424 A different outcome is raised by the authors when, in the presence of BF 3 .Et 2 O, a cationic Ni(I) with BF 4 − as the counterion is formed and proposed to be the relevant active catalyst. 425 Additionally, alcohols are presented by Saraev et al as promoters of such Ni(0) systems, 426 making possible the generation of an active Ni(II) hydride or a coordinatively unsaturated cationic Ni(I) species, described as being ten-times more active catalysts than the Ni(II) hydride. 427 On the basis of a related system, Compared with homogeneous catalysis, the identification of Ni active sites responsible for ethylene oligomerization and the determination of which mechanism occurs with Ni-based heterogeneous catalysts has witnessed few comprehensive studies.…”

Kinetic models of multi-route reactions in homogeneous catalysis with metal complexes (A Review)

“…This important reaction scheme combines the variants represented by KG7 and KG8 (class III) in Scheme 13. Alternative notions about the nature of active Ni containing cen ters in the reactions of isomerization, dimerization, and oligomerization of olefins have also been devel oped [118][119][120], including those with the possible participation of Ni(I) complexes [120]. [121][122][123][124][125][126] and Hoveida [127,129] Catalysts Simplified Scheme 15 [1] includes the steps of nucleation of an active center (K1), the steps of cata Mechanistic scheme of 1 butene isomerization in the NiL 4 -H 2 SO 4 -MeOH system [1,48] [Ru]=CHPh Mechanistic scheme of olefin cross metathesis on Grubbs catalyst [1] lytic cycle with carbene complexes K1 and K2, π com plexes (π 1 , π 2 , π 3 and π 4 ), and metallacycles (σ 1 and σ 2 ), and the steps of chain termination (chain termi nation rates W o1 ,W o2 , W o3 , W o4 ) involving metallacy cles σ 1 , σ 2 , σ 3 and σ 4 .…”