The ligand effects of homogeneous Ti-based catalysts for the copolymerization of styrene ([M₁]) with 4-[(tert-butyldimethylsilyl)oxy]styrene (TBDMSS; [M₂]) were investigated by the UV/visible spectroscopic analysis. Concerning the higher yields from the copolymerization of styrene with TBDMSS, the half-sandwich type of titanocene having π-ligands compared to titanium (IV) butoxide (Ti(OBu)₄) having σ-ligands was a more effective catalysts. The silyloxy group exhibiting a negative σ value in the Hammett σ−ρ relationship reduced the activities of titanocenes. The stronger electron-donating substituent on the π-ligand leading to the increase in the catalytic activity in syndiospecific polymerization of styrene contributed to the decrease of the reactivity of the “cationlike” metal center due to both electronic and steric effects. The reactivity ratios, r₁ and r₂, in the η⁵-indenyl trichlorotitanium ((Ind)TiCl₃)-catalyzed copolymerization of styrene with TBDMSS in the presence of methylaluminoxane (MAO) ([Al]/[Ti] = 2000) were 0.997 and 7.27 from the evaluation of Finmann and Ross, respectively. The r₁r₂ product value (7.25) indicates that a block type of copolymer may be produced in a relatively high feed range of TBDMSS to styrene.

中文翻译：

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合成和聚表征（苯乙烯Ç ö -4 - [（叔丁基二甲基硅烷基）氧基]苯乙烯）为羟基-官能化间规聚苯乙烯的前体

通过紫外/可见光谱分析研究了均相Ti基催化剂对苯乙烯（[M ₁ ]）与4-[（叔丁基二甲基甲硅烷基）氧基]苯乙烯（TBDMSS; [M ₂ ]）的共聚作用。关于苯乙烯与TBDMSS共聚的更高收率，与丁醇钛（IV）（Ti（OBu）₄）具有σ-配体是更有效的催化剂。在哈米特σ-ρ关系中表现出负σ值的甲硅烷基氧基会降低钛烷的活性。π-配体上更强的供电子取代基导致苯乙烯间同聚合反应中催化活性的增加，这归因于电子和空间效应，导致“阳离子样”金属中心的反应性降低。反应竞聚率，[R ₁和- [R ₂，在η ⁵ -茚基三氯（（茚基）的TiCl ₃Finman和Ross的评估分别表明，在甲基铝氧烷（MAO）（[Al] / [Ti] = 2000）存在下，）苯乙烯与TBDMSS的共聚反应分别为0.997和7.27。的[R ₁ - [R ₂积值（7.25）表示共聚物的块类型可TBDMSS与苯乙烯的相对高进料的范围内产生。