二氧化硅负载的阳离子环戊二烯基锆配合物的合成、表征及其乙烯聚合活性

Synthesis, characterization, and activity in ethylene polymerization of silica supported cationic cyclopentadienyl zirconium complexes.

作者信息

Millot Nicolas, Soignier Sophie, Santini Catherine C, Baudouin Anne, Basset Jean-Marie

机构信息

Laboratoire de Chimie Organométallique de Surface, UMR 9986 CNRS--ESCPE Lyon, 43 bd du 11 Novembre 1918, F-69626 Villeurbanne Cedex, France.

出版信息

J Am Chem Soc. 2006 Jul 26;128(29):9361-70. doi: 10.1021/ja060420+.

DOI:10.1021/ja060420+

PMID:16848471

Abstract

CpZrMe3 reacts with silica pretreated at 800 degrees C, SiO(2-(800)) through two pathways: (a) protolysis of a Zr-Me group by surface silanols and (b) transfer of a methyl group to the surface by opening of strained siloxane bridges, in a relative proportion of ca. 9/1, respectively, affording a well-defined surface species [([triple bond]SiO)ZrCp(Me)2], 3, but with two different local environments 3a, [([triple bond]SiO)ZrCp*(Me)2][[triple bond]Si-O-Si[triple bond]], and the other with 3b, [structure: see text]. The reaction of the species 3 with B(C6F5)3 is controlled by this local environment and gives three surface species ([triple bond]SiO)ZrCp*(Me)[MeB(C6F5)3]- [[triple bond]Si-O-Si[triple bond]], 4a (20%), ([triple bond]SiO)ZrCp*(Me)[(Me)B(C6F5)3]- [[triple bond]Si-Me], 4b (10%), and ([triple bond]SiO)2ZrCp*(Me)B(C6F5)(3)[[triple bond]Si-O-Si[triple bond]], 5 (70%). On the contrary, the reaction of CpZr(Me)3, Cp2Zr(Me)2 with [triple bond]SiO-B(C6F5)3[HNEt2Ph]+, 6, leads to a unique species ([triple bond]SiO)B(C6F5)3[CpZr(Me)2.NEt2Ph]+, 7, and ([triple bond]SiO)ZrCp2[(Me)B(C6F5)3]-, 9 respectively. The complexes 4 and 7 are active catalysts in ethylene polymerization at room temperature, 93 and 67 kg PE mol Zr1- atm(-1) bar(-1), respectively, indicating that covalently bounded Zr catalyst 4 is slightly more active than the "floating" cationic catalyst 7.

摘要

CpZrMe₃与在800℃下预处理的二氧化硅SiO(₂-(800))通过两条途径反应：(a) 表面硅醇对Zr-Me基团的质子解作用，以及(b) 通过打开应变硅氧烷桥将甲基转移到表面，相对比例分别约为9/1，生成一种定义明确的表面物种[([三键]SiO)ZrCp(Me)₂]，即3，但具有两种不同的局部环境3a，[([三键]SiO)ZrCp*(Me)₂][[三键]Si-O-Si[三键]]，另一种为3b，[结构：见原文]。物种3与B(C₆F₅)₃的反应受这种局部环境控制，生成三种表面物种[([三键]SiO)ZrCp*(Me)]⁺[MeB(C₆F₅)₃]- [[三键]Si-O-Si[三键]]，即4a（20%），[([三键]SiO)ZrCp*(Me)]⁺[(Me)B(C₆F₅)₃]- [[三键]Si-Me]，即4b（10%），以及[([三键]SiO)₂ZrCp*]⁺[(Me)B(C₆F₅)(3)]⁻[[三键]Si-O-Si[三键]]，即5（70%）。相反，CpZr(Me)₃、Cp₂Zr(Me)₂与[[三键]SiO-B(C₆F₅)₃]⁻[HNEt₂Ph]⁺，即6的反应，分别生成独特的物种[([三键]SiO)B(C₆F₅)₃]⁻[CpZr(Me)₂.NEt₂Ph]⁺，即7，以及[([三键]SiO)ZrCp₂]⁺[(Me)B(C₆F₅)₃]⁻，即9。配合物4和7在室温下是乙烯聚合的活性催化剂，活性分别为93和67 kg PE mol Zr⁻¹ atm⁻¹ bar⁻¹，这表明共价键合的Zr催化剂4比“浮动”阳离子催化剂7的活性略高。