- Trans-bis[1,3-bis(2,4,6-trimethylphenyl)imidazolidin-2-ylidene] dichlorinickel(II): Synthesis and structure
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trans-Bis[1,3-bis(2,4/6-trimethylphenyl)imidazolidin-2-ylidene] dichloronickel(II), [NiCl2(SIMes)2], was synthesized in a one-pot reaction of fluorenyllithium with nickel(II) bromide followed by the addition of 1,3-bis(2,4,6-trimethylphenyl)imidazolidinium chloride. Labile difluorenyl-nickel, formed in the course of the reaction, behaves differently than nlckelocene and indenocene in analogous reactions. It exchanges both fluorenyl ligands giving the title compound. The crystal and molecular structure of this compound have been determined by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic crystal system with square-planar geometry around the central nickel atom.
- KozioL, Andrzej,Pasynkiewicz, Stanislaw,Pietrzykowski, Antoni,Jerzykiewicz, Lucjan B.
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- Neutral ansa-bis(fluorenyl)silane neodymium borohydrides: Synthesis, structural study and behaviour as catalysts in butadiene-ethylene copolymerisation
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The reaction of silylene-bridged bis(fluorenyl)dipotassium salts with neodymium tris(borohydride) afforded new neutral ansa-bis(fluorenyl)silane neodymium borohydrides: (Flu2SiR2)Nd(BH4)(THF) [R2 = Me2, Et2, (CH2)3, Me(Ph), Flu = C13H8] that were better characterised and more soluble than the previously described anionic [(Flu2SiMe 2)Nd(BH4)2]-. The X-ray structures of three of these complexes were determined, and their solid-state geometrical parameters are very similar, despite the ring strain introduced by the silacyclobutane bridge in [Flu2Si(CH2)3] Nd(BH4)(THF). The main geometrical features were satisfactorily reproduced by DFT calculations. The catalytic activity of the title complexes in ethylene-butadiene copolymerisation reactions was assessed and compared to that of the reported activity of [(Flu2SiMe2)Nd(BH 4)2]- under similar conditions. From these results it can be concluded that the cyclo-copolymerisation of ethylene with butadiene is characteristic of a catalyst featuring silylene-bridged bis(fluorenyl) ligands around neodymium, and appears to be independent of the substituents at the silicon atom.
- Cortial, Guillaume,Le Goff, Xavier-Frederic,Bousquie, Magali,Boisson, Christophe,Le Floch, Pascal,Nief, Franois,Thuilliez, Julien
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- METALLOCENE COMPOUND, CATALYST COMPOSITION COMPRISING THE SAME, AND OLEFINIC POLYMERS PRODUCED USING THE SAME
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The present invention relates to a novel metallocene compound, a catalyst composition comprising the same, and to olefinic polymers produced using the same. The metallocene compound according to the present invention and the catalyst composition comprising the same can be used when producing olefinic polymers, have outstanding copolymerisation properties, and can produce olefinic polymers of high molecular weight. In particular, when the metallocene compound according to the present invention is employed, highly heat resistant block copolymers can be produced, and olefinic polymers can be produced which have a high melting point (Tm) even if the comonomer content is increased when producing the olefinic polymer.
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Page/Page column 7
(2012/06/18)
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- Silver-catalyzed coupling reactions of alkyl halides with indenyllithiums
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Coupling reactions of tertiary and secondary alkyl halides with indenyllithiums proceeded effectively in the presence of a catalytic amount of silver bromide to provide tertiary- and secondary-alkyl-substituted indene derivatives in good yields.
- Someya, Hidenori,Yorimitsu, Hideki,Oshima, Koichiro
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experimental part
p. 5993 - 5999
(2010/09/10)
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- 7Li, 31P, and1H pulsed Gradient Spin-Echo (PGSE) diffusion NMR spectroscopy and ion pairing: On the temperature dependence of the ion pairing in Li(CPh3), fluorenyllithium, and Li[N(SiMe 3)2] amongst other salts
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7Li, 31P, and 1H variable-temperature pulsed gradient spin-echo (PGSE) diffusion methods have been used to study ion pairing and aggregation states for a range of lithium salts such as lithium halides, lithium carbanions, and a lithium amide in THF solutions. For trityllithium (2) and fluorenyllithium (9), it is shown that ion pairing is favored at 299 K but the ions are well separated at 155 K. For 2-lithio-1,3-dithiane (13) and lithium hexamethyldisilazane (LiHMDS 16), low-temperature data show that the ions remain together. For the dithio anion 13, a mononuclear species has been established, whereas for the lithium amide 16, the PGSE results allow two different aggregation states to be readily recognized. For the lithium halides LiX (X = Br, Cl, I) in THF, the 7Li PGSE data show that all three salts can be described as well-separated ions at ambient temperature. The solid state structure of trityllithium (2) is described and reveals a solvent-separated ion pair formed by a [Li(thf)4]+ ion and a bare triphenylmethide anion.
- Fernandez, Ignacio,Martinez-Viviente, Eloisa,Breher, Frank,Pregosin, Paul S.
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p. 1495 - 1506
(2007/10/03)
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- TRANSITION METAL COMPOUNDS WITH DONOR-ACCEPTOR INTERACTION AND A SPECIAL SUBSTITUTION PATTERN
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The invention relates to compounds, in which a transition metal comprising at least two ligand systems is complexed and at least two of said systems are reversibly linked to one another by at least one bridge consisting of a donor and an acceptor, whereby at least one fluorenyl ligand is included and at least one substituent of the acceptor group is an alkyl or aryl radical. The invention also relates to the use of said compounds with donor-acceptor interaction as polymerisation catalysts for producing high-molecular elastomers.
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Page/Page column 32
(2010/02/06)
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- Contribution to the chemistry of boron, 245: Deprotonation of B,B'-Di- tert-butyl-b,b'-difluorenyldiborane(4) and the structure of the Di-tert- butyl-difluorenylidenediborate(2-) anion
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In contrast to the deprotonation of the diorganyl(fluorenyl)boranes tBu2B(fl-H) and Me2B(fl-H), which cannot be achieved uniformly, the deprotonation of B2(tBu)2(fl-H)2 in THF proceeds smoothly to give the anion B2(tBu)2(fl)22-. The isolated salts have been identified as [Na(thf)(n)]2[B2tBu2(fl)2] and [Na(thf)(OEt2){Na(OEt2)2}][B2tBu2(fl)2]. The X-ray structure of the latter compound reveals a longer B-B bond [1.744(9) A] than that in the parent compound B2(tBu2)(fl-H)2 [1.687(7) A]. One sodium center is coordinated to the five-membered ring of one fluorenylidene substituent, while the other is coordinated to three C atoms of one of the six-membered rings. This results in a rather asymmetric structure. Each sodium center is also coordinated by two ether ligands.
- Littger, Ralf,Noeth, Heinrich
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p. 1571 - 1579
(2007/10/03)
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- Formation of tetrabenzodispirotridecatetraene by a titanium mediated fluorenyl coupling reaction
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Treatment of 1,3-propanediol-ditosylate with fluorenyllithium yields 1,3-bis(fluorenyl)propane (5).Subsequent addition of methyllithium gives the corresponding dilithio compound 6.Dilithio-1,3-bis(fluorenyl)propane (6) was treated with titanium tetrachloride to yield the organic tertabenzodispirotridecatetraene product 7, presumably formed by menas of a carbon-carbon coupling reaction involving syubstituted fluorenyl radicals.The arganic compounds 5 and 7 were identified by X-ray crystal structure analyses.Keywords: Titanium; Tetrabenzodispiro(4,3,4)tridecatetraene; coupling reaction; Metallocenes; Crystal structure
- Fritze, Cornelia,Erker, Gerhard,Froehlich, Roland
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- Cyclopentadiene type compounds and method for making
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New fluorenyl silane compounds and method for their production are disclosed. The fluorenyl compounds have the formula STR1 wherein Z is a substituted or unsubstituted fluorenyl radical and Z' is a substituted or unsubstituted cyclopentadienyl-type radical or a halogen.
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- Carbanion Rearrangements by Intramolecular 1,ω Proton Shifts, IV. The Reaction of ω,ω-Diphenylalkyllithium Compounds: Proof for an Intramolecular Transmetallation Reaction by Crossover Experiments Using Isotopic Labelled Starting Material
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3,3-Diphenylpropyllithium (2) and 2-(9-fluorenyl)ethyllithium (43) do not show a 1,3 proton shift but splitt off ethylene.On the other hand 4,4-diphenylbutyllithium (19) in diethyl ether can be forced to rearrange to 1,1-diphenylbutyllithium (18) by the addition of THF.The half reaction time for this 1,4 proton shift was found to be about 4 minutes.Proof for the intramolecular character of this transmetallation reaction was obtained by crossover experiments with specifically deuterated starting material.The 1,5 proton shift with 5,5-diphenylpentyllithium (12) occurs considerably slower than the 1,4 shift with 4,4-diphenylbutyllithium (19).The rearrangement also takes place in pure diethyl ether although with a half reaction time of about 2 days.Only 3-(9-fluorenyl)propyllithium (41) in diethyl ether spontaneously shows rearrangement already at -30 deg C, whereby 9-propyl-9-fluorenyllithium (42) is formed by a 1,4 proton shift.A 1,ω phenyl migration according to Grovenstein-Zimmerman in no case could be observed.
- Maercker, Adalbert,Passlack, Michael
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p. 710 - 723
(2007/10/02)
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- Fluorenylsilanes,I: Preparation and Structural Investigation of Fluorenylsilanes with Functional Groups at Silicon
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Chloro-9-fluorenyldiphenylsilane (3a) and 9-fluorenyltris(trimethylsilyl)silane (3b) have been prepared by the reaction of the corresponding halosilanes with 9-fluorenyl lithium.The chloro substituent in 3a can be exchanged for other functional groups.With alkaline conditions cleavage of the fluorenyl-silicon bond may happen.The molecular structures of 3b and 9-fluorenyldiphenylsilanole (6a) have been determined by X-ray diffraction.In both compounds the substituents at the Cfluorenyl-Si bond are exactly staggered.The fluorenyl group in 3b is slightly folded, the Cfluorenyl-Si bond is lengthened to 194.7 (4) pm.
- Rengstl, Alfred,Schubert, Ulrich
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p. 278 - 288
(2007/10/02)
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- METAL-SILICON BONDED COMPOUNDS. XV. THE REACTIONS OF (LiSiMe3)6 AND (LiSiMe3)2*(TMEDA)3 WITH AROMATIC SUBSTRATES
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(LiSiMe3)6 (I) reacts with tetramethylenediamine (TMEDA) to yield crystalline product (LiSiMe3)2*(TMEDA)3 (II).The reactions of I and II with simple aromatic and unsaturated compounds have been examined.I reacts with derivatives containing acid protons including RCCH and fluorene in a fashion similar to organolithium derivatives, yielding simple metalated products and Me3SiH.II also reacts with these derivatives to give the methylated products but with benzene it yields trimethylphenylsilyl and LiH quantitatively.With toluene and other methylated benzenes II attacks the methyl substituent and LiH and the trimethylsilylmethyl-substituted benzene derivatives are produced.A possible mechanism for this reaction has been proposed.
- Balasubramanian, R.,Oliver, John P.
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