Highly efficient microwave-accelerated preparation of β-ketoimines

Lee, Dong Hwan; Park, Sang-Eon; Cho, Kyuho; Kim, Younsoo; Athar, Taimur; Lee, Ik-Mo

doi:10.1016/j.tetlet.2007.09.143

Cited by 23 publications

(10 citation statements)

References 20 publications

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“…The outcome would be interesting if ligand is connected to the NˆO system because ligand should be replaced with incoming olefin monomer during the process of polymerization. As β‐ketoamino complexes have drawn interest owing to their higher thermal stability and their versatility, by changing the imine substituents, for tailoring their reactivity and volatility 50. Here, our interest is keen on the well‐defined, stable, and easily synthesized complexes of nickel and palladium bearing β‐ketoamine ligands (Scheme ).…”

Section: Introductionmentioning

confidence: 99%

“…As b-ketoamino complexes have drawn interest owing to their higher thermal stability and their versatility, by changing the imine substituents, for tailoring their reactivity and volatility. 50 Here, our interest is keen on the welldefined, stable, and easily synthesized complexes of nickel and palladium bearing b-ketoamine ligands (Scheme 1). In this study, we have examined the homopolymerization of NB and the efficient copolymerization NB with 5-norbornene-2carboxylic acid methyl ester (NB-COOCH 3 ) using novel nickel and palladium complexes in the presence of B(C 6 F 5 ) 3 .…”

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confidence: 99%

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Ni(II) and Pd(II) complexes bearing benzocyclohexane–ketoarylimine for copolymerization of norbornene with 5‐norbornene‐2‐carboxylic ester

Liu

Chen

et al. 2012

J. Polym. Sci. A Polym. Chem.

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A serial of late transition metal complexes, which bearing Benzocyclohexane-ketoarylimine ligand and named as Mt(benzocyclohexane-ketoarylimino) 2 {Mt(bchkai) 2 : Mt¼Ni or Pd; bchkai¼C 10 H 8 (O)CN(Ar)CH 3 ; Ar¼naphthyl or fluoryl}, have been synthesized and characterized. The molecular structures of the ligands and nickel complex have been confirmed by Xray single-crystal analyses. The nickel complexes exhibited very high activity up to 2.7 Â 10 5 g polymer /mol Ni Áh and palladium complexes showed high activity up to 2.3 Â 10 5 g polymer / mol Pd Áh for norbornene (NB) homo-polymerization with tris (pentafluorophenyl)borane as cocatalyst. The four complexes were effective for copolymerization of NB and 5-norbornene-2carboxylic acid methyl ester (NB-COOCH 3 ) in relatively high activities (0.1-2.4 Â 10 5 g polymer /mol Mt Áh) and produced the addition-type copolymers with relatively high molecular weights (0.5 Â 10 5 -1.2 Â 10 5 g/mol) as well as narrow molecular weight distributions (PDI < 2 for all polymers). Influences of the metals and comonomer feed content on the polymerization activity as well as on the incorporation rates (20.9-42.6%) were investigated. The achieved NB/NB-COOCH 3 copolymers were confirmed to be noncrystalline, exhibited good thermal stability (T d > 400 C) and showed good solubility in common organic solvents. V C 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: [4695][4696][4697][4698][4699][4700][4701][4702][4703][4704] 2012

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Ni(II) and Pd(II) complexes bearing benzocyclohexane–ketoarylimine for copolymerization of norbornene with 5‐norbornene‐2‐carboxylic ester

Liu

Chen

et al. 2012

J. Polym. Sci. A Polym. Chem.

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“…18 A variety of catalysts such as hydrochloric acid, sulphuric acid, p-toluenesulphonic acid, acetic acid, trimethylsilyltrifluoromethanesulfonate (TMSTf), montmorillonite clay K10 under microwave irradiation or ultrasound, NaAuCl 4 Á2H 2 O, iodine, aluminum oxide, silica gel, cerium trichloride, natural clays and InBr 3 have been employed to effect this transformation. [19][20][21][22][23][24][25][26] Recently these compounds have been prepared by direct condensation of b-dicarbonyl compounds and primary amines in water solvent. 27 However these methods suffer from one or more drawbacks, such as the use of expensive or less readily available reagents and bases, vigorous reaction conditions, longer reaction times, unsatisfactory yields, low selectivity or the use of toxic solvents, which limit these methods to small scale synthesis.…”

Section: Introductionmentioning

confidence: 99%

Cu/AlO(OH)-catalyzed formation of β-enamino ketones/esters under solvent, ligand and base free conditions – experimental and computational studies

Babu

Thomas

Nijamudheen

et al. 2012

Catal. Sci. Technol.

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Cu/AlO(OH) has been found to be an efficient catalyst for the formation of b-enamino ketones/ esters under solvent, ligand and base free conditions. The catalyst Cu/AlO(OH) is prepared from CuCl 2 Á2H 2 O, pluronic P123 and Al(O-sec-Bu) 3 . The prepared catalyst is characterized by HR-TEM, SEM-EDX, XPS and FT-IR spectra. The b-ketoenamine is prepared using Cu/AlO(OH) as catalyst under mild and environmentally benign conditions. The reaction conditions are optimized with different catalyst amounts and temperatures using an acetylacetone and aniline system as a model. The scope of the reaction is extended to different types of diketones and amines. Solvent, ligand and base free and room temperature conditions make the reaction interesting from both an economic and environmental point of view. A mechanism is proposed on the basis of DFT calculations.

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“…Especially, β-ketoamine late transition metal complexes have drawn interest due to their higher thermal stability and versatility, by changing the imine substituents, for tailoring their reactivity and volatility. 3 Since the development of the homogenous catalysts for NB additional polymerization, few studies on heterogeneous catalysts have been carried out. 4 In the mid 1990s, Brookhart introduced α-diimine Ni(II) late transition metal catalysts for the slurry-phase polymerization of ethylene and reported on covalently anchored complexes to enhance activity and prevent leaching from the surface, which is a method that allows ready use of a range of activators and improves the activities.…”

Section: Introductionmentioning

confidence: 99%

Silica-supported Ni(II) complex bearing [O^N] ligand and copolymerization to afford silica hybrid polynorbornenes nanocomposites

Yuan

Chen

et al. 2012

High Performance Polymers

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In situ polymerization is an ideal technique to make a perfect dispersion of nanosilica into polymer matrixes. So, in this article, a novel silica-supported β-ketoamine nickel(II) dibromide precatalyst was efficiently prepared and used in in situ slurry polymerizations of norbornene (NB) to afford a highly productive NB addition polymerization system in combination with tris(pentafluorophenyl)borane (B(C6F5)3) cocatalyst. It exhibited productivity of 176.8 kg of polynorbornene (mol Ni)−1 h−1 at a mole ratio of B/Ni = 20, and the catalyst deactivation kinetics in the early stage of polymerization fitted well by the first-order deactivation kinetics up to about 60 min. The catalyst system was also effective for the copolymerization of NB and 5-norbornene-2-carboxylic acid methyl ester to produce the addition-type copolymers with high-molecular-weights (3.28–3.45 × 105 g mol−1) and incorporation rates (8.1–49.1%) as well as narrow molecular weight distributions (polydispersity index = 1.6). The nanoparticles were confirmed to be well-dispersed in the polymer matrix with each individual nanoparticle surrounded by polymer. Transparency of nanocomposites could be kept up to about 60%. The brittleness of polymer was obviously improved, and the tensile strength of polymer film could be as high as 47.8 MPa.

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Highly efficient microwave-accelerated preparation of β-ketoimines

Cited by 23 publications

References 20 publications

Ni(II) and Pd(II) complexes bearing benzocyclohexane–ketoarylimine for copolymerization of norbornene with 5‐norbornene‐2‐carboxylic ester

Ni(II) and Pd(II) complexes bearing benzocyclohexane–ketoarylimine for copolymerization of norbornene with 5‐norbornene‐2‐carboxylic ester

Cu/AlO(OH)-catalyzed formation of β-enamino ketones/esters under solvent, ligand and base free conditions – experimental and computational studies

Silica-supported Ni(II) complex bearing [O^N] ligand and copolymerization to afford silica hybrid polynorbornenes nanocomposites

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