Half-sandwich chromium(<scp>iii</scp>) complexes bearing β-ketoiminato and β-diketiminate ligands as catalysts for ethylene polymerization

Huang, Yuan–Biao; Jin, Guo‐Xin

doi:10.1039/b820798b

Cited by 51 publications

(36 citation statements)

References 34 publications

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“…Moreover, some of the metal complexes stabilized by -ketoiminate ligands exhibit exciting reactivity in homogeneous catalysis, such as for polymerization and copolymerization of olefins [1][2][3][4][5] , and the ring-opening polymerization of cyclic esters [6][7][8] . As one of the derivatives of -ketoiminate ligands, the N-aryloxo-functionalized -ketoimines containing a pendant phenol functionality have been employed in main group and transition-metal coordination chemistry [9] , but not in lanthanide chemistry until our recent work [10] .…”

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confidence: 99%

Synthesis and characterization of N-aryloxo-functionalized β-ketoiminate rare-earth complexes and their catalytic activity for the polymerization of ɛ-caprolactone

Han

Yao

et al. 2009

Chin. Sci. Bull.

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et al. Synthesis and characterization of N-aryloxo-functionalized ß-ketoiminate rare-earth complexes and their catalytic activity for the polyme-rization of ε-caprolactone. The synthesis and characterization of dimeric rare-earth amides stabilized by a dianionic N-aryloxo functionalized β-ketoiminate ligand are described. Reactions of 4-(2-hydroxy-5-methyl-phenyl) imino-2-pentanone (LH 2 ) with Ln[N(SiMe 3 ) 2 ] 3 (μ-Cl)Li(THF) 3 in a 1:1 molar ratio in THF gave the dimeric rare-earth amido complexes [LLn{N(SiMe 3 ) 2 }(THF)] 2 [Ln = Nd (1), Sm (2), Yb (3), Y (4)]. These complexes were well characterized, and the definitive molecular structures of complexes 3 and 4 were determined. It was found that complexes 1-4 can initiate the ring-opening polymerization of ε-caprolactone, and the ionic radii of the central metals have significant effect on the catalytic activity. rare earth, β-ketoiminate ligand, amide, synthesis, polymerization, ε-caprolactoneOver the past few years, -ketoiminate ligands have become one of the most attractive chelating systems in main group and transition metal coordination chemistry, because of their easy preparation from inexpensive and readily available starting materials and sample modification of both steric and/or electronic properties. Moreover, some of the metal complexes stabilized by -ketoiminate ligands exhibit exciting reactivity in homogeneous catalysis, such as for polymerization and copolymerization of olefins [1][2][3][4][5] , and the ring-opening polymerization of cyclic esters [6][7][8] . As one of the derivatives of -ketoiminate ligands, the N-aryloxo-functionalized -ketoimines containing a pendant phenol functionality have been employed in main group and transition-metal coordination chemistry [9] , but not in lanthanide chemistry until our recent work [10] .Recently, we are interested in studying the synthesis and reactivity of rare-earth metal complexes supported by the N-aryloxo-functionalized -ketoiminate ligands.In our earlier work, a series of new rare-earth metal chlorides and aryloxides based on this ligand system were synthesized, finding the corresponding aryloxides are active initiators for the ring-opening polymerization of L-lactide [10] . In our consequent study in this area, we synthesized some new neutral rare-earth metal amido complexes stabilized by N-aryloxo-functionalized -ketoiminate ligand and examined their catalytic activity for the ring-opening polymerization of ε-caprolactone.

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confidence: 99%

Synthesis and characterization of N-aryloxo-functionalized β-ketoiminate rare-earth complexes and their catalytic activity for the polymerization of ɛ-caprolactone

Han

Yao

et al. 2009

Chin. Sci. Bull.

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“…The attraction of this catalyst is the low levels of AlR 3 [26]. Closely related complexes 20 and 21 were reported by the same authors [27]. Both are inactive in the presence of MAO but lead to high molecular weight polyethylene with 25 Chromium complexes of b-diketiminate (NacNac) ligands, both mono-and bisligand, were introduced by Theopold [29] and Gibson [30].…”

Section: Cr Complexes Of Cyclopentadienyl Ligands Containing Pendant mentioning

confidence: 92%

Cr Complexes of Nitrogen Donor Ligands for Olefin Oligomerisation and Polymerisation

McGuinness

2011

Catalysis by Metal Complexes

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Chromium complexes continue to play an important role as catalysts for olefin oligomerisation and polymerisation, with many of these catalysts supported by N-donor containing ligation. A number of highly active catalysts for ethylene polymerisation have been developed in recent years, as well as new catalysts for highly selective ethylene oligomerisation. New developments in this area since 2003, in which chromium complexes of N-donor ligands are utilized, are discussed in subsequent sections.

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“…Increasing the TIBA:Cr ratio beyond 35 equiv. has a negative effect on catalytic activity(Table 1, entries21,22,23).…”

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confidence: 98%

A neutral trianionic pincer [NCN]CrIV–Me complex as a highly active ethylene polymerization precatalyst

McGowan

Veige

2012

Journal of Organometallic Chemistry

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Half-sandwich chromium(iii) complexes bearing β-ketoiminato and β-diketiminate ligands as catalysts for ethylene polymerization

Abstract: Half-sandwich chromium(iii) complexes bearing beta-ketoiminato and beta-diketiminate ligands were synthesized and employed as catalysts for ethylene polymerization in the presence of triethylaluminium.

Cited by 51 publications

References 34 publications

Synthesis and characterization of N-aryloxo-functionalized β-ketoiminate rare-earth complexes and their catalytic activity for the polymerization of ɛ-caprolactone

Synthesis and characterization of N-aryloxo-functionalized β-ketoiminate rare-earth complexes and their catalytic activity for the polymerization of ɛ-caprolactone

Cr Complexes of Nitrogen Donor Ligands for Olefin Oligomerisation and Polymerisation

A neutral trianionic pincer [NCN]CrIV–Me complex as a highly active ethylene polymerization precatalyst

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