160824-61-3Relevant academic research and scientific papers
Synthesis and characterization of new alkoxide and aryloxide derivatives of titanium and zirconium. X-ray molecular structure of
Amor, J. I.,Burton, N.C.,Cuenca, T.,Gomez-Sal, P.,Royo, P.
, p. 153 - 160 (1995)
Lithium or sodium alkoxides MOR (R = CH2CH-CMe2; M = Li 1; Na 2; R = C6F5; M = Li 3) were prepared by reaction of the alcohols with n-butyl lithium or sodium metal in hexane.Reaction of a hexane suspension of 3 with SiClMe3 afforded SiMe3(OC6F5) 4, whereas the reaction of 3 equivalents of C6F5OH with AlMe3 in hexane led to Al(OC6F5)3 5.Compounds 1 or 2 react with one equivalent of *Cl2Me> (Cp* = C5Me5) in toluene to give *ClMe(OCH2CH=CMe2)> 6.Complex 6 reacts with AlEtCl2 to give quantitatively *Cl3>.In the presence of water, the hydrolysis of 6 takes place giving the μ-oxo compound *Cl)(μ-O)>3>. *Cl2Me> reacted with an excess of the alcohol C6F5OH to give *(OC6F5)3> 7. reacted with two equivalents of pentafluorophenol in the presence of aniline to give the dialkoxide 8.When the same reaction was carried out in a 1:1 molar ratio, a mixture of 8 and the chloroalkoxide 9 was obtained.A clean reaction takes place when the μ-oxo compound is treated with two equivalents of pentafluorophenol, leading to the isolation of the alkoxo complex 2(μ-O)> 10.The methylalkoxo derivative 11, was obtained by reaction of with one equivalent of 3.Alternative methods can also be followed to synthesize 8 and 11.The crystal and molecular structure of 8 has been determined by X-ray diffraction methods.The most interesting feature of this structure is the disposition of the (C6F5) ring planes, which are located practically on the reflection plane defined by O(1), Zr(1) and O(1)'. Keywords: Titanium; Zirconium; Alkoxides; X-ray diffraction; Group 4; Cyclopentadienyl
Dehydrocoupling polymerization of arylsilanes with chloro(aryloxy)bis(cyclopentadienyl)zirconium complex catalysts
Obora, Yasushi,Tanaka, Masato
, p. 1 - 11 (2007/10/03)
Complexes generated by treating chloro(aryloxy)bis(cyclopentadienyl)zirconium [3; aryloxy=2,6-di-tert-butyl-4-methylphenoxy (3a), 2,6-diisopropylphenoxy (3b), phenoxy (3c), 2,3,4,5,6-pentafluorophenoxy (3d), and 2,6-dimethoxyphenoxy (3e)] with one equivalent of n-BuLi catalyze dehydrocoupling polymerization of arylsilanes 1 [aryl=phenyl (1a), p-methoxyphenyl (1b), p-dimethylaminophenyl (1c), p-methylthiophenyl (1d)] at room temperature to afford corresponding polysilanes. Their catalytic performance was compared with the conventional system generated from dichlorobis(cyclopentadienyl)zirconium (4) and two equivalents of n-BuLi. The reaction of 1a using 3a/n-BuLi, 3b/n-BuLi or 3c/n-BuLi gave high-molecular-weight polysilanes (Mw=13.3×103 and Mn=5.8×103 with 3a; Mw=10.4×103 and Mn=4.2×103 with 3b; Mw=8.8×103 and Mn=5.3×103 with 3c). Formation of the polysilane was fast in comparison with 4, in particular when the catalyst was ligated by a sterically demanding (3a) or electron-withdrawing (3d) aryloxy group. The time course of the gel permeation chromatography profiles suggested that complex 3a showed faster chain growth than 3d, 3e and 4. The extent of the formation of undesired cyclics was relatively small (10%) in the sterically demanding 3a/n-BuLi- or 3b/n-BuLi-catalyzed reaction.
