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为了研究茂环上的苄基对双核茂金属催化行为的影响,合成了含有苄基的桥连双核茂金属[(η~5-C_5H_5)TiCl_2(η~5-(C_6H_5)C(Me)_2(C_5H_3)]2[μ,μ-1,4-(CH_2)2(C_6H_4)][(TiBz)_2],通过~1HNMR、~(13)C NMR、质谱和元素分析进行了表征,确认了化学结构.在甲基铝氧烷(MAO)助催化作用下(TiBz)_2催化乙烯聚合得到C(4)支链的聚乙烯,C(4)支链源自于苄基苯环弱作用效应导致的乙烯三聚产生的1-己烯对聚乙烯插入.该催化体系具有很好的共聚能力,催化乙烯与1-己烯共聚时,聚合物中1-己烯插入率高达13.7 mol%,且形成交替共聚片段结构.对其特殊的催化循环机理进行了探讨,苄基苯环与中心金属弱相互作用导致1-己烯与乙烯分子交替插入得到己烯乙烯交替共聚(HEHE)片段,聚合物较窄的分子量分布(PDI=2.23)表明,在聚合过程中两个金属中心产生了强烈的协同效应,使其共聚能力大幅度提高.
In order to study the effect of the benzyl group on the catalytic activity of the binuclear metallocene, a series of benzyl-containing bridged dinuclear metallocenes [(η 5-C 5 H 5) TiCl 2 (η 5- (C 6 H 5) C (Me) (C_5H_3)] 2 [μ, μ-1,4- (CH_2) 2 (C_6H_4)] [(TiBz) _2] was characterized by ~ 1H NMR, ~ 13 C NMR, mass spectrum and elemental analysis. Chemical structure.The C (4) branched polyethylene was obtained by the polymerization of ethylene with (TiBz) _2 catalyzed by methylaluminoxane (MAO). The C (4) branch was derived from the weak effect of benzylbenzene 1-hexene produced by the trimerization of ethylene is inserted into the polyethylene.The catalytic system has a good copolymerization ability, and when the ethylene is copolymerized with 1-hexene, the insertion rate of the 1-hexene in the polymer is as high as 13.7 mol% And the formation of an alternating copolymerization fragment structure of its special catalytic cycle mechanism were discussed benzyl benzyl ring and the central metal weak interaction led to the 1-hexene and ethylene molecules alternately inserted hexene ethylene alternate copolymerization (HEHE) fragments, polymerization The narrower molecular weight distribution (PDI = 2.23) shows that there is a strong synergistic effect between the two metal centers during the polymerization process, resulting in a substantial increase in the copolymerization ability.