Synthesis of chiral unbridged zirconocene complexes: Applications in the polymerization of ethylene and propylene

详细信息	查看全文 | 推荐本文 |

• 作者：Dorian Polo-Ceró ; n ; Santiago Gó ; mez-Ruiz ; Sanjiv Prashar ; Mariano Fajardo ; Antonio Antiñ ; olo ; Antonio Otero ; Isabel Ló ; pez-Solera ; Manuel L. Reyes
• 关键词：Metallocenes ; Zirconium ; Polymerization ; Polyethylene ; Polypropylene
• 刊名：Journal of Molecular Catalysis A ; Chemical
• 出版年：2007
• 期刊代码：57_13811169
• 类别：ch
• 出版时间：1 May 2007
• 卷：268
• 期：1-2
• 页码：264-276
• 文件大小：392 K

摘要

The lithium derivatives of the chiral substituent bearing cyclopentadienyl ligands, Li{C₅H₄(CHRR′)} (R = Prⁱ, R′ = Me (1); R = Prⁱ, R′ = Ph (2); R = Bu^t, R′ = Me (3); R = Bu^t, R′ = Ph (4)), were prepared via the reaction of alkyllithium compounds with the corresponding fulvene reagent. The mixed cyclopentadienyl zirconocene complexes [Zr(η⁵-C₅H₅)(η⁵-C₅H₄{CHRR′})Cl₂] (R = Prⁱ, R′ = Me (5); R = Prⁱ, R′ = Ph (6); R = Bu^t, R′ = Me (7); R = Bu^t, R′ = Ph (8)) were prepared via the reaction of the lithium precursors 1–4 with [Zr(η⁵-C₅H₅)Cl₃]. The symmetrical zirconocene complexes, [Zr(η⁵-C₅H₄{CHRR′})₂Cl₂] (R = Prⁱ, R′ = Me (9); R = Prⁱ, R′ = Ph (10); R = Bu^t, R′ = Me (11); R = Bu^t, R′ = Ph (12)), were synthesized from the reaction of two molar equivalents of 1–4 with ZrCl₄. When the mono(cyclopentadienyl) complexes [Zr(η⁵-C₅H₄{CHRR′})Cl₃] (R = Prⁱ, R′ = Me (17); R = Prⁱ, R′ = Ph (18); R = Bu^t, R′ = Me (19); R = Bu^t, R′ = Ph (20)) were reacted with Li(C₉H₇) the zirconocene derivatives, [Zr(η⁵-C₉H₇)(η⁵-C₅H₄{CHRR′})Cl₂] (R = Prⁱ, R′ = Me (21); R = Prⁱ, R′ = Ph (22); R = Bu^t, R′ = Me (23); R = Bu^t, R′ = Ph (24)), were obtained. The molecular structure of 11 has been determined by single-crystal X-ray diffraction studies. 5–12 and 21–24 have been tested as catalysts in the polymerization of ethylene and propylene. Isotactic polypropylene with [mmmm] pentads between 20 and 40%were obtained and their tacticity can be related directly to the structure of the catalyst.