Cobalt-β-diimine complexes for ethylene oligomerization

Caovilla, Marcela; Thiele, Daniel; Souza, Roberto Fernando de; Gregório, José Ribeiro; Bernardo-Gusmão, Kátia

doi:10.1016/j.catcom.2017.08.002

Cited by 5 publications

(2 citation statements)

References 23 publications

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“…NˆN bi-dentate ligand cobalt complexes were found to exhibit high activity and selectivity for dimerization. Katia et al [136] investigated three cobalt-β-diimine complexes 41-43 (Figure 13) for ethylene oligomerization. At 10 bar, 30 • C, using EASC as a co-catalyst and toluene as a solvent, complex 42 exhibited the highest activity (TOF = 34 s −1 ), while the TOF of complex 43 was only 0.8 s −1 .…”

Section: Tri-dentate Cobalt Complexmentioning

confidence: 99%

Ethylene Oligomerization Catalyzed by Different Homogeneous or Heterogeneous Catalysts

Peng,

Huang,

2024

Catalysts

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Linear α-olefins (LAOs) are linear alkenes with double bonds at the ends of the molecular chains. LAOs with different chain lengths can be widely applied in various fields. Ethylene oligomerization has become the main process for producing LAOs. In this review, different homogeneous or heterogeneous catalysts recently reported in ethylene oligomerization with Ni, Fe, Co, Cr, etc., as active centers will be discussed. In the homogeneous catalytic system, we mainly discuss the effects of the molecular structure and the electronic and coordination states of complexes on their catalytic activity and selectivity. The Ni, Fe, and Co homogeneous catalysts are discussed separately based on different ligand types, while the Cr-based homogeneous catalysts are discussed separately for ethylene trimerization, tetramerization, and non-selective oligomerization. In heterogeneous catalytic systems, we mainly concentrate on the influence of various supports (metal–organic frameworks, covalent organic frameworks, molecular sieves, etc.) and different ways to introduce active centers to affect the performance in ethylene oligomerization. Finally, a summary and outlook on ethylene oligomerization catalysts are provided based on the current research. The development of highly selective α-olefin formation processes remains a major challenge for academia and industry.

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Section: Tri-dentate Cobalt Complexmentioning

confidence: 99%

Ethylene Oligomerization Catalyzed by Different Homogeneous or Heterogeneous Catalysts

Peng,

Huang,

2024

Catalysts

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“…Thiele and de Souza prepared a series of Co(II)‐based catalysts bearing N^N^N‐type ligands and obtained catalytic activities of up to 3.4 × 10 5 g (mol Co ) −1 h −1 , with excellent selectivity (96.9%) towards 1‐butene. Caovilla and co‐workers reported a series of cobalt β‐diimine complexes for ethylene oligomerization that achieved high catalytic activity (2.1 × 10 6 g (mol Co ) −1 h −1 ) and high selectivity (84%) towards 1‐butene. Transition metals supported by diphosphine ligands have been investigated extensively for use in selective ethylene oligomerizations .…”

Section: Introductionmentioning

confidence: 99%

Cobalt(II)‐based ethylene dimerization catalysts with silicon‐bridged diphosphine ligands

Wei

Yu²,

Alam

et al. 2018

Applied Organom Chemis

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A series of ligands and cobalt complexes were synthesized and characterized using NMR spectroscopy, elemental analysis and single-crystal X-ray diffrac-features a monomeric structure with κ 2 coordination of the silicon-bridged diphosphine ligand to the cobalt center.Using dried methylaluminoxane (DMAO) and AlEt 3 as co-catalysts and methylcyclohexane as solvent, the Co(II) complex proved to be moderately active and highly selective for ethylene dimerization. The effects of ligand structure, catalyst loading, reaction temperature, Al/Co molar ratio, DMAO/ AlEt 3 molar ratio and reaction time were investigated with respect to the catalytic activity and product selectivity of ethylene dimerization. Cobalt complex C1 exhibited moderate catalytic activity of 2.3 × 10 5 g (mol Co ) −1 h −1 , with 100% selectivity towards C 4 (87% 1-C 4 in the C 4 fraction).

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Two mononuclear cobalt(III) complexes exhibiting phenoxazinone synthase activity

Mahato

Hecke

Nayek

2018

Applied Organom Chemis

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ClO 4 ⋅MeOH (1) (tmtp = tri(m-tolyl)phosphine) and [LCo(PPh 3 )(H 2 O)]PF 6 (2), have been prepared from a polydentate ligand, N,N′-bis(3methoxysalicylidehydene)cyclohexane-1,2-diamine (H 2 L). Standard analytical techniques such as elemental analysis and UV-visible and Fourier transform infrared spectroscopies were used to characterize both complexes. The solidstate molecular structures of both complexes were confirmed from single-crystal X-ray diffraction analysis. Structural analyses show that the Co(III) ion occupies the centre of a distorted octahedron in a complex cation: [LCo(tmtp) (H 2 O)] + and [LCo(PPh 3 )(H 2 O)] + for 1 and 2, respectively. Phenoxazinone synthase activities of both complexes were screened. Kinetic studies and other experimental observations reveal that the reaction follows rate saturation kinetics and proceeds through the formation of a catalyst (complex)-substrate adduct. The turnover number (K cat ) of complex 2 is 54.07 h −1 , exhibiting better catalytic activity compared to 1 (K cat = 45.11 h −1 ). KEYWORDS cobalt(III) complex, phenoxazinone synthase activity, Schiff base, single-crystal X-ray diffraction, turnover number | INTRODUCTIONSchiff bases cover an enormous area in coordination chemistry predominantly due to their smooth synthesis, controllability of steric and electronic environment and diversity in applications. [1] Schiff bases can easily accommodate single or multiple metal ions of various oxidation states. [2] Judicial selection of Schiff bases and metal ions often results in homo-or heteronuclear metal complexes including those of transition metals and main group elements. [3] Depending on the nature of the ligands and metal ions, these complexes exhibit structural diversities and open up applications in several areas such as biology, [4] catalysis, [5] materials science [6] and magnetism. [7] Interestingly, salen-type ligands, which are prepared from various diamines and salicylaldehyde derivatives, are most widely explored among all Schiff bases in coordination chemistry. [8] Modification of salicylaldimine ligands, for example by anchoring a methoxy group (-OMe) on the salicylaldimine moiety, increases their denticity making the ligands more prone to form polynuclear complexes. [9] Numerous examples of metal complexes of Schiff base ligands have been reported in the literature. However, metal complexes containing cobalt(II/III) ions have recently started to receive attention. [10] Cobalt(II/ III) complexes of Schiff base ligands find important applications in magnetism, [11] biochemistry [12] and catalysis. [13] These complexes have been used in mimicking important biological co-factors such as phenoxazinone synthase, [14] photosynthesis, [15] methionine aminopeptidase, [16] cobalamin, etc. Among these, phenoxazinone synthase facilitates the conversion of o-aminophenol

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Cobalt-β-diimine complexes for ethylene oligomerization

Cited by 5 publications

References 23 publications

Ethylene Oligomerization Catalyzed by Different Homogeneous or Heterogeneous Catalysts

Ethylene Oligomerization Catalyzed by Different Homogeneous or Heterogeneous Catalysts

Cobalt(II)‐based ethylene dimerization catalysts with silicon‐bridged diphosphine ligands

Two mononuclear cobalt(III) complexes exhibiting phenoxazinone synthase activity

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