One Ligand Fits All:  Cationic Mono(amidinate) Alkyl Catalysts over the Full Size Range of the Group 3 and Lanthanide Metals

Bambirra, Sergio; Bouwkamp, Marco W.; Meetsma, Auke; Hessen, Bart

doi:10.1021/ja0475297

Cited by 249 publications

(165 citation statements)

References 23 publications

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“…Only a limited number of fully characterized mono-and dicationic alkyl complexes of the rare-earth metals has been described, [36,41,42] and the potential of such species in olefin polymerization catalysis remains unexplored. [36,42,54,60,61,65,68,75] For other organic transformations, two instructive examples have recently appeared in the literature. [77,90] Cationic lanthanide alkyl derivatives as homogeneous catalysts appear to be generally superior to their neutral precursors due to their increased electrophilicity towards substrate molecules.…”

Section: Resultsmentioning

confidence: 99%

“…[42] C NMR spectra of the THF adduct suggest the presence of a weakly coordinating anion in solution. [22] Treatment of the scandium derivative [ScCp*(CH 3 ) 2 {O ¼ P(CMe 3 ) 3 }] with one equivalent of B(C 6 F 5 ) 3 in toluene gives the crystallographically characterized contact ion pair [ScCp*(CH 3 ){O ¼ P(CMe 3 ) 3 }(m-CH 3 )B(C 6 F 5 ) 3 ] as a relatively thermally stable compound.…”

Section: Cationic Alkyl Complexes Containing Lx-type Ligandsmentioning

confidence: 99%

“…[65] Interestingly, the yttrium precursor appears to provide the most effective catalyst for ethylene polymerization, as both larger and smaller metals show lower activity under standardized conditions. [42] Activation of the triazacyclononane derivative [Sc(L-1)-(CH 3 , M w /M n ¼ 1.3). [60] Interestingly, the tris(trimethylsilylmethyl) derivative [Sc(L-1)(CH 2 SiMe 3 ) 3 ] showed a significantly enhanced activity.…”

Section: Polymerization Of Ethylene and A-olefinsmentioning

confidence: 99%

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Cationic Alkyl Complexes of the Rare‐Earth Metals: Synthesis, Structure, and Reactivity

2005

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This contribution is dedicated to Dick Schrock on the occasion of his 60th birthday.Abstract: Cationic alkyl complexes of the rare-earth metals [LnR m ; L ¼ Lewis base) were virtually unknown species until recently. Because of their increased Lewis acidity/electrophilicity they should have considerable potential as homogeneous catalysts in olefin polymerization and in organic transformations. They can be generated by treating the neutral rare-earth metal precursors containing at least two alkyl groups R with suitable Lewis or Brønsted acids in the presence of weakly coordinating anions. Not only monocationic but also dicationic alkyl derivatives have been shown to be accessible. In the context of modeling homogeneous ethylene polymerization using a mixture consisting of LnR 3 /AlR 3 /[NMe 2 HPh][B(C 6 F 5 ) 4 ], such dications were discovered. Some thermally robust examples of mono-and dicationic alkyl complexes have been structurally characterized as solvent-separated ion pairs. Neutral and monoanionic macrocycles such as crown ethers or aza-crown ethers as well as amidinato, b-diketiminato, and substituted cyclopentadienyl ligands are suitable ancillary ligands to stabilize the cationic alkyl fragments.

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Section: Resultsmentioning

confidence: 99%

Section: Cationic Alkyl Complexes Containing Lx-type Ligandsmentioning

confidence: 99%

Section: Polymerization Of Ethylene and A-olefinsmentioning

confidence: 99%

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Cationic Alkyl Complexes of the Rare‐Earth Metals: Synthesis, Structure, and Reactivity

2005

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“…Recently, however, there has been intense interest and spectacular progress in the synthesis of rare earth metal dialkyl complexes bearing one anionic ancillary ligand (LMR 2 ), and aside from the ubiquitous bulky cyclopentadienyl ligands [2] various non-cylopentadienyl ligands have been successfully enlisted. [3] However, most of the studies have focused on the Group 3 metals Sc and Y, and only the works of Hou et al [4] and Hessen et al [5] have included the range of lanthanide metals.…”

Section: In Memory Of Jerry Trofimenkomentioning

confidence: 99%

Scorpionate‐Supported Dialkyl and Dihydride Lanthanide Complexes: Ligand‐ and Solvent‐Dependent Cluster Hydride Formation

et al. 2008

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Non‐cyclopentadienyl lanthanide dihydrides [{(TpR,R′)LnH2}n] (R,R′=Me, n=4; R,R′=H, n=6) and [{(Tp Me 2)YH2}3(thf)2–3] were isolated and characterized. Their polynuclear frameworks are maintained in solution, and their nuclearity depends on the ligand and the solvent used in their preparation. The structure of [{(Tp Me 2)YH2}4] is shown (B red, H white, N blue, Y orange). TpR,R′=tris(3‐R‐5‐R′‐pyrazolyl)borate.

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“…[197] . 稀土三烷基配合物和大立体位阻脒基配体进行烷烃消除反应, 可合成一系列的单脒基稀土双烷基配合物, 其再与硼盐反应生成相应的稀土单烷基阳离子配合物(图 37) [198] . 这些稀土单烷基阳离子配合物可以催化乙烯聚合, 催化活性强烈依赖于 Ln 3＋的离子半径, 最大的 La [204] , 通过控制 [Ap′K] n 或 [Ap*K] n 的用量也能得到氯化物和二氯化物 [205,206] .…”

Section: β-二亚胺稀土金属有机配合物 β-二亚胺是最为重要的双齿配体unclassified

Sixty Years of the Chemistry of Rare-earth Organometallic Complexes

Changtao¹,

Wang²,

Chen³

2014

Acta Chim. Sinica

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Rare-earth elements include scandium, yttrium and fifteen lanthanides. Since Wilkinson and Birmingham reported the fist example of rare-earth organometallic complex, the chemistry of rare-earth organometallic complexes has had a great advance during the past sixty years. A variety of Cp containing rare-earth metal complexes, including mono-Cp, bis-Cp, and tri-Cp complexes, have been synthesized. Variation of the size of substituent on Cp ring, introducing the nitrogen or oxygen containing pendant arm to Cp ring or using ansa bis-Cp ligands make the synthesis and stabilization of these three types of rare-earth metal Cp complexes available. The Cp related ligands, such as indenyl and fluorenyl, also have been applied for the rare-earth organometallic complexes. From 1990's, there was a tendency to explore the rare-earth organometallic complexes with ancillary ligands beyond Cp and its derivatives in order to search for more efficient rare-earth metal catalysts. Non-Cp ligands, such as biphenolates, β-diketiminates, amidinates, guanidinates, etc. have been introduced into the chemistry of rare-earth organometallic complexes, and a larger number of non-Cp rare-earth organometallic complexes have been synthesized and characterized. The application of non-cyclopentadienyl ligands not only resulted in the rare-earth organometallic complexes with new structural features, but also the catalysts with high activity and high selectivity for the polymer synthesis and organic synthesis. The rare-earth organometallic complexes catalyze homo-and co-polymerization of olefins as well as specific polymerization of dienes and polar monomers. The discovery of the catalytic system composed of the neutral rare-earth metal dialkyls/borate enables to synthesize some interesting polymers which are difficult to be prepared by using other catalytic system. The rare-earth organometallic complexes are also able to catalyze some important organic reactions, such as hydroamination, hydrophosphinylation, and hydroalkoxylation, etc. Different from the late-translation metal catalyzed organic reactions, most of the rare-earth metal catalyzed ones do not involve oxidative addition and reductive elimination steps. The review describes some important developments of the chemistry of rare-earth organometallic complexes in the past sixty years.

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One Ligand Fits All: Cationic Mono(amidinate) Alkyl Catalysts over the Full Size Range of the Group 3 and Lanthanide Metals

Cited by 249 publications

References 23 publications

Cationic Alkyl Complexes of the Rare‐Earth Metals: Synthesis, Structure, and Reactivity

Cationic Alkyl Complexes of the Rare‐Earth Metals: Synthesis, Structure, and Reactivity

Scorpionate‐Supported Dialkyl and Dihydride Lanthanide Complexes: Ligand‐ and Solvent‐Dependent Cluster Hydride Formation

Sixty Years of the Chemistry of Rare-earth Organometallic Complexes

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