881-04-9Relevant articles and documents
Trans-bis[1,3-bis(2,4,6-trimethylphenyl)imidazolidin-2-ylidene] dichlorinickel(II): Synthesis and structure
KozioL, Andrzej,Pasynkiewicz, Stanislaw,Pietrzykowski, Antoni,Jerzykiewicz, Lucjan B.
, p. 609 - 617 (2007)
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.
METALLOCENE COMPOUND, CATALYST COMPOSITION COMPRISING THE SAME, AND OLEFINIC POLYMERS PRODUCED USING THE SAME
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Page/Page column 7, (2012/06/18)
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.
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
Fernandez, Ignacio,Martinez-Viviente, Eloisa,Breher, Frank,Pregosin, Paul S.
, p. 1495 - 1506 (2007/10/03)
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.