亚乙基桥联双茚锆、铪配合物的合成及催化丙烯选择性齐聚研究:茚环3-位取代基的影响  

Synthesis of Ethylene-Bridged Bis(indenyl)Zirconium,Hafnium Complexes and Their Catalytic Behavior on Selective Propylene Oligomerization:the Effect of 3-Substituent on Indenyl Ring

作　　者：李波 周海燕 马海燕[1] 黄吉玲[1] Li Bo;Zhou Haiyan;Ma Haiyan;Huang Jiling(Laboratory of Organometallic Chemistry,School of Chemistry and Molecular Engineering,East China University of Science and Technology,Shanghai 200237)

机构地区：[1]华东理工大学化学与分子工程学院、金属有机化学研究室,200237

出　　处：《化学学报》2023年第10期1280-1294,共15页Acta Chimica Sinica

基　　金：国家自然科学基金(No.21274041)资助.

摘　　要：设计并合成了12个亚乙基桥联双茚类锆、铪配合物meso-/rac-1~7[ansa-C_(2)H_(4)-(3-R-4,7-Me_(2)-C_(9)H_(3))_(2)MCl_(2):M=Zr,R=^(n)Bu(meso-/rac-1),^(i)Pr(meso-2),CH_(2)Cy(meso-/rac-3),Bn(meso-/rac-4),CH_(2)C_(6)H_(4)(4-CH_(3))(meso-/rac-5);M=Hf,R=CH_(2)C_(6)H_(4)(4-CH_(3))(meso-/rac-7);ansa-C_(2)H_(4)-{2-Me-3-Bn-5,6-[1,3-(CH_(2))_(3)]C_(9)H_(2)}_(2)ZrCl_(2)(meso-6)].所有配合物均通过了核磁共振(1H NMR、13C NMR)和元素分析(EA)的鉴定,其中配合物rac-1、meso-1、meso-2、meso-4、meso-5和meso-6的空间结构进一步通过X射线单晶衍射确证.在助催化剂甲基铝氧烷(MAO)存在下,茚环3-位为烷基取代的锆配合物meso-/rac-1~3催化丙烯齐聚主要得到分子量为几百至几千的丙烯齐聚物,活性最高可达9.73×10^(6) g·mol-Zr^(-1)·h^(-1),同时表现出较低的β-Me消除选择性,齐聚产物烯丙基端基含量最高为41.3%.茚环3-位为苄基或取代苄基的双茚锆、铪配合物meso-/rac-4~7催化丙烯齐聚主要得到丙烯二聚体,为1-戊烯、2-甲基-1-戊烯、4-甲基-1-戊烯、2,4-二甲基-1-戊烯的混合物.温度为影响丙烯二聚活性的主要因素,其中配合物rac-4在80℃时催化丙烯二聚活性可高达1.24×10^(6) g·mol-Zr^(-1)·h^(-1).二聚物的分布受温度及Al/Zr比的影响不大.铪配合物rac-7表现出较高的β-Me消除选择性,最高可达60.1%.Oligomerization of propylene or otherα-olefins is the main way to obtain various branchedα-olefins,which are potential comonomers for the preparation of novel polymers with excellent properties or building blocks for manufacturing fine chemicals.Due to the different coordination-insertion and chain transfer modes involved in the oligomerization process of propylene,propylene oligomers with different structures were generally obtained,thus developing novel catalysts capable of catalyzing selective propylene oligomerization attracts great attention.In this work,a series of novel ethylene-bridged bis(indenyl)complexes meso-/rac-1~7[ansa-C_(2)H_(4)-(3-R-4,7-Me_(2)-C_(9)H_(3))_(2)MCl_(2):M=Zr,R=^(n)Bu(meso-/rac-1),^(i)Pr(meso-2),CH_(2)Cy(meso-/rac-3),Bn(meso-/rac-4),CH_(2)C_(6)H_(4)(4-CH_(3))(meso-/rac-5);M=Hf,R=CH_(2)C_(6)H_(4)(4-CH_(3))(meso-/rac-7);an-sa-C_(2)H_(4)-{2-Me-3-Bn-5,6-[1,3-(CH_(2))_(3)]C_(9)H_(2)}_(2)ZrCl_(2)(meso-6)]were synthesized via the reaction of the dilithium salts of the proligands with 1 equiv.of ZrCl_(4) or HfCl_(4) in Et_(2)O,and in most of the cases,both the rac-and meso-isomers were separated in analytically pure forms via recrystallization.All complexes were characterized by nuclear magnetic resonances(^(1)H NMR,^(13)C NMR)and elemental analysis(EA)methods.The molecular structures of typical complexes rac-1,meso-1,meso-2,me-so-4,meso-5 and meso-6 were further determined by X-ray single crystal diffraction studies.The solid-state molecular struc-tures of these complexes exhibit essentially similar geometrical parameters.The bond lengths between zirconium center and carbon atoms of the π-bonding five-membered ring of the indenyl unit vary slightly,suggesting a η^(5)-coordination mode of the five-membered rings.In the presence of methylaluminoxane(MAO)as the cocatalyst,zirconium complexes meso-/rac-1~3 with an alkyl group on the 3-position of the indenyl ring catalyzed the oligomerization of propylene with high activities up to 9.73×10^(6) g·mol-Zr^(-1)·h^(-1),affording propylene olig

关 键 词：茂金属配合物 催化剂 丙烯 齐聚 二聚 

分 类 号：O641.4[理学—物理化学] O621.251[理学—化学]