Synthesis of {1,3-bis(η5-tetramethylcyclopentadienyl)-1,1,3,3-tetramethyldisiloxane}dichlorotitanium(IV) via hydrolysis of bis{η5-(N,N-dimethylaminodimethylsilyl)tetramethylcyclopentadienyl}dichlorotitanium(IV)

Group 4 metallocene complexes with non-bridged and tetramethyldisiloxane-bridged methyl-phenyl-cyclopentadienyl ligands: synthesis, characterization and olefin polymerization studies

“…As shown in Scheme 2, reaction of the lithium salt Li [1-Ph-3-Me-C 5 H 3 ] 1 [16] with 0.5 equivalents of ZrCl 4 in hexane gave the dicyclopentadienyl zirconium complex [Zr{g 5 -(1-Ph-3-Me-C 5 H 3 )} 2 Cl 2 ] 2 which was isolated as a yellow microcrystalline solid in 74% yield and characterized by elemental analysis and NMR spectroscopy.…”

“…Consistently both isomers also show almost identical sets of signals in their 13 C NMR spectra (see Section 4). Alkylation of this mixture (meso-2 + rac-2) with 2 equivalents of LiMe and MgCl(CH 2 Ph) gave meso-rac mixtures of the corresponding dimethyl and dibenzyl zirconium complexes [Zr{g 5 -(1-Ph-3-Me-C 5 H 3 )} 2 R 2 ] (R=Me meso-3 + rac-3, CH 2 Ph meso-4 + rac-4) which were isolated as white (3) and yellow (4) microcrystalline solids and identified by elemental analysis and NMR spectroscopy. A definitive structural assignment of the meso-3 isomer was easily made because its NMR spectra show two singlets ( 1 H) and two signals ( 13 C) due to two non-equivalent zirconium-methyl groups whereas the rac-3 isomer shows one signal ( 1 H and 13 C) for both equivalent zirconium-methyl groups.…”

“…Some lanthanide and group 4 tetramethyldisiloxane-bridged ansa-metallocenes related to the ferrocenophane derivative reported previously [2] have been isolated. We reported [3,4] 2 Cl 2 ] and similar hydrolytic cleavage of SiNMe 2 bonds gave the tetramethylcyclopentadienyl titanium derivative [5]. These group 4 metal [6] and similar praseodymium and ytterbium [7] compounds with unsubstituted and t-butyl-substituted [6,8] cyclopentadienyl rings were isolated following the method reported for the first titanium derivative [9], by reaction of the metal halides with the sodium or potassium salts of the dicyclopentadienyl ligand.…”

“…Related doubly-disiloxane-bridged [12,13] and di-and polynuclear monocyclopentadienyl-type titanium complexes [14] have also been isolated and their catalytic activity for styrene polymerization studied [15]. Except for [Ti{(g 5 show the lateral location of the disiloxane bridge with respect to the MCl 2 moiety (Scheme 1(a)) with both cyclopentadienyl rings twisted to bring closer two carbon atoms located in a position with respect to the bridge.…”

“…We were interested in studying the effect of these disubstituted rings on the behaviour of ansa-metallocenes bridged by the tetramethyldisiloxane group compared with the corresponding unbridged metallocenes. In this work we describe the synthesis and structural characterization of [Zr{g 5 -(1-Ph-3-Me-C 5 H 3 )} 2 X 2 ] and [Zr(g 5 -C 5 H 5 ){g 5 -(1-Ph-3-Me-C 5 H 3 )}X 2 ] (X = Cl, Me, CH 2 Ph) zirconocene complexes with non-bridged cylopentadienyl rings and tetramethyldisiloxane-bridged ansa-metallocene derivatives [M{g 5 -(Me-Ph-C 5 H 2 SiMe 2 ) 2 O}X 2 ] (M = Zr, Hf; X = Cl, Me, CH 2 Ph) containing the MePh-disubstituted cyclopentadienyl ligand. The catalytic activity of the dichlorozirconocenes combined with MAO for ethene and propene polymerization has been evaluated.…”