The monopotassium salt of the ligand of a Ziegler–Natta catalyst

Schaefer, William P.; Cotter, W. Donald; Bercaw, John E.

doi:10.1107/s0108270193001842

Cited by 13 publications

(5 citation statements)

References 3 publications

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“…The differences in metal coordination produce other distinctive differences between the two structures. For example, the angle between the Cp′ planes in 1 is 147.7°, which is similar to the angles found in K[( t -BuNHSiMe 2 )Cp](thf) (145.5°), K[C 5 Me 5 ](py) 2 (138°), and K[Cp](OEt 2 ) (145°) . The interplanar Cp′ angles are nearly perpendicular (88.8°) in K[Me 2 P(2-Me-4- t- Bu-C 5 H 2 ] 2 , however.…”

Section: Resultssupporting

confidence: 71%

s-Block Metal Complexes of the Bis(tetramethylcyclopentadienyl) Phosphonium Diylide [Me(t-Bu)P(C₅Me₄)₂]⁻

et al. 2008

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Treatment of the phosphonium salt [Me(t-Bu)P(C 5 Me 4 H) 2 ]I with 2 equiv of KH produces the coordination polymer {K[Me(t-Bu)P(C 5 Me 4 ) 2 ](thf)} ∞ . If the phosphonium salt reacts with a single equivalent of KH followed by Ca[N(SiMe 3 ) 2 ] 2 , the calcium complex [Me(t-Bu)P(C 5 Me 4 ) 2 ]CaN(SiMe 3 ) 2 is produced, which is structurally related to Cp′ 2 LnX organolanthanides. Density functional theory studies of the H 3 E (E ) C, Si, P)-substituted cyclopentadienyl ring indicate that the energy required for outof-plane bending of the substituent decreases in the order H 3 C > H 3 Si > H 3 P.

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Section: Resultssupporting

confidence: 71%

s-Block Metal Complexes of the Bis(tetramethylcyclopentadienyl) Phosphonium Diylide [Me(t-Bu)P(C₅Me₄)₂]⁻

et al. 2008

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“…Moreover, all attempts to prepare dipotassium derivatives of the ligand system, [8] for example by exchange reaction of the dilithium derivatives with two equivalents of KOtBu in hexane or toluene, were also unsuccessful. The complete double metalation of the aminocyclopentadienes (C 5 Me 4 H)SiMe 2 NHR (R ϭ Et, allyl, nPr, tBu) was achieved by reaction with two equivalents of potassium 1,2-diphenylethenide in THF at room temperature, as indicated by the disappearance of the characteristic color of the radical anion [PhCHCHPh] ·Ϫ upon addition of the aminocyclopentadiene.…”

Section: Resultsmentioning

confidence: 98%

Di‐ and Trivalent Ytterbium Complexes Containing Linked Amino‐ and Amidocyclopentadienyl Ligands

2003

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Reactions of the aminocyclopentadienes (C5Me4H)SiMe2NHR (R = Et, allyl, nPr, tBu) with [YbI2(THF)2] in the presence of two equivalents of potassium 1,2‐diphenylethenide in THF at room temperature gave the diamagnetic half‐sandwich complexes [Yb(η5‐C5Me4SiMe2NHR)Ln(μ‐I)]2 (L = THF, n = 2, L = DME, n = 1). The tert‐butylamido derivative [Yb(η5‐C5Me4SiMe2NHtBu)(THF)2(μ‐I)]2 was characterized by X‐ray structural analysis as a dinuclear complex containing a nonchelating aminocyclopentadienyl ligand. Deprotonation of the aminocyclopentadiene (C5H4tBu)SiMe2NHtBu with two equivalents of potassium 1,2‐diphenylethenide in THF, followed by reaction with [YbI2(THF)2] at 60 °C, gave the trivalent ytterbium ate complex [K(DME)][Yb{(η5:η1‐C5H3tBu‐3)SiMe2NtBu}2]. A single crystal X‐ray diffraction study of this complex shows polymeric chains consisting of trivalent ytterbocene units with two chelating amidocyclopentadienyl ligands coordinated to potassium ions. Metalation of the aminoindene (C9H7)SiMe2NHtBu under the same conditions and treatment with [YbI2(THF)2] in THF at ambient temperature resulted in the formation of the divalent ytterbocene complex [Yb{η5‐(1‐C9H6)SiMe2NHtBu}2(THF)2]. The reaction of ytterbium naphthalenide [Yb(C10H8)(THF)2] with one equivalent of (C9H7)SiMe2NHtBu afforded the bis(indenyl) compound which was isolated as its 2,2′‐bipyridyl adduct [Yb{η5‐(1‐C9H6)SiMe2NHtBu}2(bipy)]. It was shown by single‐crystal structural analysis to exhibit a bent metallocene structure with noncoordinating amino side‐chains. The reaction of (C5Me4H)CH2SiMe2NHtBu, which contains a longer CH2SiMe2 bridge, with [Yb(C10H8)(THF)2] gave the complex [Li0.5][Yb(μ‐η5:η1‐C5Me4CH2SiMe2NtBu)(THF)2(μ‐I)0.5]. Single crystal X‐ray structure analysis revealed the presence of polymeric chains consisting of dinuclear iodo‐bridged [Yb(η5:η1‐C5Me4CH2SiMe2NtBu)] units with a chelating linked amidocyclopentadienyl ligand, intermolecularly bridged by lithium ions. The lithium ions are bonded in an η5‐manner to both units, forming a lithocene structure. When YbCl3 was reacted with Li2[(C5H3tBu‐3)SiMe2NCH2CH2X] (X = NMe2, OMe), heterobimetallic complexes Li[Yb{(η5:η1‐C5H3tBu‐3)SiMe2NCH2CH2X}2] with a helical metallocene structure were isolated. The single crystal structure analysis of one of the three possible diastereomers of Li{Yb[(η5:η1‐C5H3tBu‐3)SiMe2NCH2CH2NMe2]2}, viz. the thermodynamically stable (R,R)/(S,S) epimer was performed. When YbCl3 was reacted with one equivalent of Li2[(C5H3tBu‐3)SiMe2NCH2CH2NMe2] and reduced “in situ” with one equivalent of sodium 1,2‐diphenylethenide in THF, the ytterbium(II) metallocene complex [Li(THF)]2[Yb{(η5‐C5H3tBu‐3)SiMe2NH(CH2CH2NMe2)}2(μ‐Cl)2] was isolated, which exhibits a structure with the two amino functions coordinating to the lithium ions and the chloro ligands bridging both the lithium and ytterbium centers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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“…Because cyclopentadienes are more acidic than amines, one would expect the cyclopentadiene to react more easily with the alkyl complex 1 than with the amine. However, one of the coordinated THF molecules in 1 seems to be displaced by the additional donor site in the side chain of the linked amido−cyclopentadienyl ligand.…”

Section: Resultsmentioning

confidence: 99%

Single-Component Polymerization Catalysts for Ethylene and Styrene: Synthesis, Characterization, and Reactivity of Alkyl and Hydrido Yttrium Complexes Containing a Linked Amido−Cyclopentadienyl Ligand

et al. 1999

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3 )(THF) can be prepared in high yields by a σ-bond metathesis reaction between Y(CH 2 SiMe 3 ) 3 (THF) 2 and amino-functionalized cyclopentadienes or indene. The structure of Y(η 5 :η 1 -C 5 Me 4 SiMe 2 NCMe 2 Et)(CH 2 SiMe 3 )(THF) was shown by single-crystal X-ray diffraction to be that of a three-legged piano stool. Reaction of Y(CH 2 -SiMe 3 ) 3 (THF) 2 with the tridentate linked amido-cyclopentadienyl ligands (C 5 Me 4 H)SiMe 2 -NHR (R ) CH 2 CH 2 OMe, CH 2 CH 2 NMe 2 , CH 2 CH 2 CH 2 OMe, CMe 2 CH 2 OMe), which contain an additional donor site, results in the cleavage of the silicon-cyclopentadienyl bond and the formation of the tetramethylcyclopentadienyl complexes Y(η 5 -C 5 Me 4 H){N(SiMe 2 CH 2are prepared in good yields by hydrogenolysis of the corresponding alkyl complexes. Variable-temperature 1 H, 13 C, 29 Si, and 89 Y NMR spectroscopic data show that the hydrido complexes retain their dimeric structure in solution on the NMR time scale but that they undergo fluxional processes which include THF dissociation and cis-trans isomerization. The presence of monomeric species is inferred from 1 H NMR spectroscopic detection of the crossover product [Y(η 5 :η 1 -C 5 Me 4 SiMe 2 NCMe 3 )(THF)(µ-H) 2 Y(η 5 :η 1 -C 5 Me 4 -SiMe 2 NCMe 2 Et)(THF)], which forms within minutes at 50 °C when [Y(η 5 :η 1 -C 5 Me 4 SiMe 2 -NCMe 2 R)(THF)(µ-H)] 2 with R ) Me and Et are mixed in C 6 D 6 . Ethylene is polymerized with moderate activity by the hydrido complexes, whereas styrene derivatives and 1-hexene are cleanly converted into the monoinsertion products. 1,5-Hexadiene reacts with the hydrido complexes to give the monomeric cyclopentylmethyl complex Y(η 5 :η 1 -C 5 Me 4 SiMe 2 NCMe 3 ){CH 2 -CH(CH 2 ) 4 }(THF). The 1-phenylethyl complexes Y(η 5 :η 1 -C 5 Me 4 SiMe 2 NCMe 3 ){CH(CH 3 )(C 6 H 3 -2-R-4-R′)}(THF) (R ) R′ ) H; R ) H, R′ ) OMe; R ) R′ ) Me), selectively formed by secondary insertion of the corresponding styrene derivatives, show fluxional η 3 -coordination in solution. A monomeric structure with a weak η 3 -interaction was confirmed by single-crystal X-ray diffraction of Y(η 5 :η 1 -C 5 Me 4 SiMe 2 NCMe 2 Et){CH(CH 3 )(C 6 H 4 -4-tBu)}(THF). The insertion product of 1-hexene is dimeric in solution, but partially loses THF under vacuum. This product initiates the polymerization of styrene to give atactic polystyrenes with narrow molecular weight distributions (M w /M n 1.10-1.23) and microstructures enriched in syndiotacticity (rr ≈ 70%).

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The monopotassium salt of the ligand of a Ziegler–Natta catalyst

Cited by 13 publications

References 3 publications

s-Block Metal Complexes of the Bis(tetramethylcyclopentadienyl) Phosphonium Diylide [Me(t-Bu)P(C₅Me₄)₂]⁻

s-Block Metal Complexes of the Bis(tetramethylcyclopentadienyl) Phosphonium Diylide [Me(t-Bu)P(C₅Me₄)₂]⁻

Di‐ and Trivalent Ytterbium Complexes Containing Linked Amino‐ and Amidocyclopentadienyl Ligands

Single-Component Polymerization Catalysts for Ethylene and Styrene: Synthesis, Characterization, and Reactivity of Alkyl and Hydrido Yttrium Complexes Containing a Linked Amido−Cyclopentadienyl Ligand

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The monopotassium salt of the ligand of a Ziegler–Natta catalyst

Cited by 13 publications

References 3 publications

s-Block Metal Complexes of the Bis(tetramethylcyclopentadienyl) Phosphonium Diylide [Me(t-Bu)P(C5Me4)2]−

s-Block Metal Complexes of the Bis(tetramethylcyclopentadienyl) Phosphonium Diylide [Me(t-Bu)P(C5Me4)2]−

Di‐ and Trivalent Ytterbium Complexes Containing Linked Amino‐ and Amidocyclopentadienyl Ligands

Single-Component Polymerization Catalysts for Ethylene and Styrene: Synthesis, Characterization, and Reactivity of Alkyl and Hydrido Yttrium Complexes Containing a Linked Amido−Cyclopentadienyl Ligand

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s-Block Metal Complexes of the Bis(tetramethylcyclopentadienyl) Phosphonium Diylide [Me(t-Bu)P(C₅Me₄)₂]⁻

s-Block Metal Complexes of the Bis(tetramethylcyclopentadienyl) Phosphonium Diylide [Me(t-Bu)P(C₅Me₄)₂]⁻