Synthesis, characterization and ethylene oligomerization studies of nickel(II) based new formazane derivatives

Zaidman, A. V.; Pervova, I. G.; Vilms, A.I.; Белов, Г. П.; Kayumov, R. R.; Слепухин, П. А.; Lipunov, I. N.

doi:10.1016/j.ica.2010.11.044

Cited by 15 publications

(9 citation statements)

References 3 publications

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“…It is important to note, however, that unlike in our earlier report where all the preformed C 4 and C 6 oligomers were subsequently alkylated to toluene, catalyst 2 partially promotes Friedel–Crafts alkylation of the toluene solvent used. Similar observations have also been made for (3,5‐dimethylpyrazol‐1‐yl)methylbenzene nickel dihalide complexes and nickel(II) complexes based on formazane derivatives . Consistent with recent studies, ethylene oligomerization reactions performed in chlorobenzene (Table , entry 11) result in the formation of mainly oligomers without any Friedel–Crafts alkylation products.…”

Section: Resultssupporting

confidence: 89%

Nickel(II) complexes bearing pyrazolylpyridines: synthesis, structures and ethylene oligomerization reactions

Nyamato

Alam

Ojwach

et al. 2015

Applied Organom Chemis

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Reactions of 2-bromo-6-(3,5-dimethyl-1H-pyrazol-1-yl)pyridine (L1) and 2,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)pyridine (L2) with NiCl 2 and NiBr 2 led to the formation of their respective metal complexes [NiCl 2 (L1)] (1), [NiBr 2 (L1)] (2) and [NiBr 2 (L2)] (3) in moderate to high yields. The complexes were characterized using elemental analyses, mass spectrometry and singlecrystal X-ray diffraction for 2. The solid-state structure of 2 confirmed the bidentate coordination mode of L1 and formation of a monometallic compound. Activation of the nickel(II) pre-catalysts with methylaluminoxane afforded active catalysts in the ethylene oligomerization reaction to produce mainly butenes (84-86%). In contrast, activation of nickel(II) pre-catalyst 2 with ethylaluminium dichloride resulted in partial Friedel-Crafts alkylation of the toluene solvent by the preformed oligomers. Complex structure, nature of co-catalyst employed, type of solvent and reaction conditions influenced the catalytic behaviour of these pre-catalysts.

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Section: Resultssupporting

confidence: 89%

Nickel(II) complexes bearing pyrazolylpyridines: synthesis, structures and ethylene oligomerization reactions

Nyamato

Alam

Ojwach

et al. 2015

Applied Organom Chemis

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“…A specimen of C 34 3 , was used for X-ray crystallographic analysis, and the X-ray intensity data were measured. The integration of the data using an orthorhombic unit cell yielded a total of 105 204 reflections to a maximum y angle of 28.461 (minimum y angle of 1.501) (0.75 Å resolution), of which 5570 were independent (average redundancy 18.888, completeness = 99.3%, R int = 14.67%, and R sig = 10.85%) and 2799 (50.25%) were greater than 2s(F 2 ).…”

Section: X-ray Crystallographic Studymentioning

confidence: 99%

Synthesis, crystal structure, optical and electrochemical properties of novel diphenylether-based formazan derivatives

2015

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In this study, formazans 5a-5h were synthesized by coupling the reactions of substituted phenylhydrazone compounds 3a-3h with diazonium salt of 4-chloro-2-phenoxybenzenamine (4). The substituted phenylhydrazones 3a-3h were obtained from the condensation of substituted phenylhydrazines 1a-1h with 4-methoxybenzaldehyde (2). The structures of the formazans were characterized by using elemental analysis, FTIR, 1 H NMR, 13 C NMR, LC-MS and the crystal structure of compound 5e was determined by X-ray crystallography. The absorption spectra of all compounds were investigated in various solvents. Although their absorption bands are only slightly dependent on the polarities of solvents, the significant change was observed by altering the electronic characteristics of the substituents. The fluorescence quantum yield properties and Stokes shifts of compounds 5a-5h in DMSO were also explored. Electrochemical properties of the new products were studied by CV measurements. In addition, computational studies were conducted at the PBE1PBE/6-311g (2d,2p) level to shed light on the structures of possible tautomers and intramolecular H-bonds.Scheme 1 Synthetic route for the formation of formazan derivatives 5a-5h.Scheme 2 Intramolecular hydrogen bonding and tautomerisation of the formazan system. View Article Onlinea Oxidation and reduction potentials from cyclic voltammograms. b Onsets of oxidation and reduction. c HOMO = À(E onset (ox) + 4.4) (eV), LUMO = À(E onset (red) + 4.4).Scheme 4 (a) Schematic representation of the structure of 5c for possible oxidation mechanisms of 5c, 5d, 5g and 5h; (b) structure of 5a for possible oxidation mechanism of 5a, 5b, 5e and 5f.

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“…43 Zaidman et al prepared a series of bis(formazanate) nickel complexes from formazans with various (heteroaromatic) substituents or linked bis-formazan scaffolds, and studied their catalytic activity in ethylene oligomerization (for representative structures 38/39, see Scheme 13b). 44 Upon treatment with AlEtCl 2 , the complexes showed some catalytic activity towards the formation of a mixture of butenes, hexenes and octenes, but also resulted in substantial amounts of (poly)ethyltoluenes by Friedel-Crafts alkylation of the toluene solvent with ethylene. Nitro-or cyanoformazans were used by Hicks et al to prepare the nickel complexes 40 and 41 (Scheme 14).…”

Section: Group 9 (Co Ir)mentioning

confidence: 99%

“…(b) Representative structures of nickel complexes described by Zaidman et al, and their application as catalysts for ethylene oligomerization. [40][41][42][43][44] Scheme 14 (a) Synthesis of homoleptic bis(formazanate) nickel complex 40. (b) Synthesis of heteroleptic cyano/nitro-formazanate nickel hydroxide complexes 41 with larger N-aryl groups.…”

Section: Group 9 (Co Ir)mentioning

confidence: 99%

Formazanate coordination compounds: synthesis, reactivity, and applications

Gilroy

Otten

2020

Chem. Soc. Rev.

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Synthesis, characterization and ethylene oligomerization studies of nickel(II) based new formazane derivatives

Cited by 15 publications

References 3 publications

Nickel(II) complexes bearing pyrazolylpyridines: synthesis, structures and ethylene oligomerization reactions

Nickel(II) complexes bearing pyrazolylpyridines: synthesis, structures and ethylene oligomerization reactions

Synthesis, crystal structure, optical and electrochemical properties of novel diphenylether-based formazan derivatives

Formazanate coordination compounds: synthesis, reactivity, and applications

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