Precise synthesis of new polyolefins by post metallocene type transition metal catalysis

本研究项目的目的是创造具有独特性能的新型聚烯烃。均相过渡金属络合催化剂的烯烃聚合在有机金属化学、催化和高分子化学等领域受到广泛关注。这是因为设计一种高效的络合催化剂是通过控制聚合进行精确合成的关键。结果表明，（环戊二烯基）（芳氧基）钛（IV）配合物Cp′ti (OAr)X_2 （OAr=芳氧基）在甲基铝氧烷（MAO）存在下对乙烯、α-烯烃的聚合具有显著的催化活性，而环戊二烯基取代基的位置直接影响了单体的反应活性和序列分布。我们还表明，通过简单的配体修饰，这种类型的催化剂可以成为苯乙烯聚合和乙烯/苯乙烯共聚的有效催化剂前驱体。我们还发现，在这种催化剂体系中，通过修饰环戊二烯基上的取代基，如（吲哚基）TiCl_2(OAr)，可以实现降冰片烯在乙烯/降冰片烯共聚中的高效掺入。在此基础上，利用该催化剂制备出了以往难以或不可能制备的新型聚烯烃。我们还探讨了配体在cp -苯胺、cp -酰胺和cp -酮胺钛配合物的烯烃聚合化学中的作用。（苯胺基）（环戊二烯基）钛（IV）型配合物Cp' trcl_2 [N(R)(XAr)] [Cp'=Cp^*, 1,3 M_2C_5H_3,Cp；R = SiMe_3等;制备了Ar=2,6- me_2c_6h_3和Cp'-酰胺钛配合物Cp' ticl_2 (NMeR)，这些配合物在MAO存在下对乙烯聚合具有较高的催化活性，其活性依次为：Cp'=Cp^*>1,3- me_2c_5h_3 >Cp。在这里观察到的趋势与Cp′-芳氧基钛配合物几乎相同。只需要替换Cp′上的取代基，就可以对共聚苯乙烯的高效催化剂进行改性。我们报道了（芳基）（芳基氧基）钒(V)配合物VCl_2(NAr)（OAr’）在MAO存在下表现出显著的乙烯聚合催化活性，并且降冰片烯的开环复分解聚合（ROMP）是由V(CH_2Ph)_2(NAr)（o - 2,6pr_2c_6h_3）引发的。用Et_2AlCl处理后，其乙烯聚合催化活性显著提高。用AlMe_3代替Et_2AlCl的催化活性较低，但用AlMe_3作为助催化剂对ROMP有较好的催化效果。我们相信这里观察到的结果将是这些聚合之间的一个有趣的对比。少

The purpose on this research project is to create new polyolefins that possess unique properties. Olefin polymerization by homogeneous transition metal complex catalysts attracts particular attention in the field of organometallic chemistry, catalysis, and polymer chemistry. This is because the design of an efficient complex catalyst has thus been the key for the precise synthesis by controlled polymerization. We have shown that (cyclopentadienyl)(aryloxy)titanium (IV) complex of the type, Cp'Ti(OAr)X_2 (OAr=aryloxy group), exhibited remarkable catalytic activities for ethylene, α-olefin polymerization in the presence of methylaluminoxane (MAO), and monomer reactivities as well as monomer sequence distributions were directly affected by the substituents in cyclopentadienyl group. We have also shown that the catalyst of this type could be tuned to the efficient catalyst precursor for both styrene polymerization and ethylene/styrene copolymerization by the simple ligand modification. We … More have also shown that efiicient norbornene incorporation in ethylene/norbornene copolymerization can be achieved in this catalyst systems by modifying the substitutent on cyclopentadienyl group like (indenyl)TiCl_2(OAr). Based on these facts, new polyolefins that were difficult/impossible to prepare have been created by using this catalysts. We also explored the effect of ligand in olefin polymerization chemistry by Cp-anilide, Cp-amide and Cp-ketimide titanium complexes. (Anilido)(cyclopentadienyl)titanium(IV)complexes of the type, Cp'TrCl_2[N(R)(XAr)] [Cp'=Cp^*, 1,3 M_2C_5H_3,Cp ; R=SiMe_3 etc.; Ar=2,6-Me_2C_6H_3], and Cp'-amide titanium complexes of the type, Cp'TiCl_2(NMeR) have been prepared, and these complexes exhibited high catalytic activity for ethylene polymerization in the presence of MAO, and the activity increased in the order : Cp'=Cp^*>1,3-Me_2C_5H_3>Cp. The trend observed here was almost the same as that in Cp'-aryloxy titanium complexes. The efficient catalyst for symdiospecific styrene polymerization could be modified only by replacing the substituent on Cp'.We have reported that (arylimido)(aryloxo)vanadium(V) complexes of the type, VCl_2(NAr)(OAr'), exhibited remarkable catalytic activities for ethylene polymerization in the presence of MAO, and that ring-opening metathesis polymerization (ROMP) of norbornene had been initiated by V(CH_2Ph)_2(NAr)(O-2,6Pr_2C_6H_3). Remarkably high catalytic activities for ethylene polymerization were observed if the complex was treated with Et_2AlCl. The low catalytic activity was observed if AlMe_3 was used in place of Et_2AlCl, although the use of AlMe_3 as cocatalyst was effective for the ROMP. We believe that the results observed here would be an interesting contrast among these polymerizations. Less