- Dissymmetric ansa zirconocene complexes with di- and trisubstituted indenyl ligands as catalysts for homogeneous ethylene homo- and ethylene/1-hexene copolymerization reactions
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Different routes for the synthesis of 1,2- and 1,2,3-substituted indene derivatives are described. Representative substituents are: Me, Ph, PhCH2, PhCH2CH2, PhCH2CH2CH2, CH2CH?=?CH2. Subsequent deprotonation of these substituted indenes and reaction with indenyl zirconium trichloride gave the corresponding dissymmetric bis(indenyl) zirconium complexes. After activation with methylaluminoxane (MAO) these complexes show high activities both in ethylene homopolymerisation and ethylene/1-hexene copolymerisation. The rate of comonomer incorporation can reach 33.3% (15/MAO). The copolymers exhibit lower melting points than the homopolymers and their crystallinities α are lower compared with the homopolymers.
- Rimkus, Andrea M.,Alt, Helmut G.
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- Asymmetric electrophilic fluorocyclization with carbon nucleophiles
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Twist of 'F'ate: Various helical-shaped fluorinated tetracyclic molecules were prepared by fluorocarbocyclization of prochiral alkenes. The development of a new class of chiral Selectfluor (1) proved instrumental in developing an asymmetric variant of this transformation. These novel chiral N-F reagents are readily accessible by fluorine transfer from shelf-stable N-fluoropyridinium salts. Copyright
- Wolstenhulme, Jamie R.,Rosenqvist, Jessica,Lozano, Oscar,Ilupeju, John,Wurz, Nathalie,Engle, Keary M.,Pidgeon, George W.,Moore, Peter R.,Sandford, Graham,Gouverneur, Veronique
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supporting information
p. 9796 - 9800
(2013/09/23)
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- Unbridged metallocene dichloride complexes with mono-substituted indenyl ligands and their application for the polymerization of propene
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The synthesis of unbridged metallocene dichloride complexes of the type Ind′2ZrCl2 (Ind′ = 2-alkyl- or arylalkyl-substituted indenyl) is described. The complexes are characterized by 1H- and 13C-NMR spectroscopy and mass spectrometry. After activation with methylalumoxane these complexes can be used for propene polymerization; they produce block copolymers consisting of alternating isotactic and atactic blocks. The polymerization results and the polymer properties are presented. The influence of the catalyst structure on the polymerization behaviour is discussed.
- Schmidt, Roland,Alt, Helmut G.
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p. 304 - 309
(2007/10/03)
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- ω-phenylalkyl-substituted zirconocene dichloride complexes as catalyst precursors for homogeneous ethylene polymerization
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The reaction of ω-phenyl-1-bromoalkanes with cyclopentadienyl sodium, indenyl lithium or fluorenyl lithium forms ω-phenylalkyl-substituted ligand precursors in high yields. The corresponding anions react with zirconium tetrachloride to give ω-phenylalkyl-
- Licht, Erik H.,Alt, Helmut G.,Karim, M. Manzurul
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p. 275 - 287
(2007/10/03)
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- AN EFFICIENT INTERMOLECULAR CARBON-CARBON BOND FORMATION VIA SmI2-PROMOTED ANION RADICAL ALKYLATION
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Anion radicals generated from the corresponding ketones with the efficient one electron transfer system, SmI2-THF-HMPA, attacked a variety of activated olefins at room temperature affording the corresponding addition products in good to excellent yields,
- Ujikawa, Osamu,Inanaga, Junji,Yamaguchi, Masaru
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p. 2837 - 2840
(2007/10/02)
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