Rodrigues Anne-Sophie, Kirillov Evgueni, Lehmann Christian W, Roisnel Thierry, Vuillemin Bruno, Razavi Abbas, Carpentier Jean-François
Sciences Chimiques de Rennes, UMR 6226 CNRS-Université de Rennes 1, 35042 Rennes Cedex, France.
Chemistry. 2007;13(19):5548-65. doi: 10.1002/chem.200601708.
A series of new neutral allyl Group 3 metal complexes bearing ansa-bridged fluorenyl/cyclopentadienyl ligands [[Flu-EMe(2)-(3-R-Cp)]Ln(eta(3)-C(3)H(5))(THF)] (E=C, R=H, Ln=Y (2), La (3), Nd (4), Sm (5); R=tBu, Ln=Y (8), Nd (9); E=Si, R=H, Ln=Y (12), Nd (13)) were synthesized in good yields via salt metathesis protocols. The complexes were characterized by elemental analysis, NMR spectroscopy for diamagnetic complexes, and single-crystal X-ray diffraction studies for 2, 4, 9 and 12. Some of the allyl ansa-lanthanidocenes, especially 4, are effective single-component catalysts for the polymerization of styrene, giving pure syndiotactic polystyrenes (rrrr > 99 %) with low to high molecular weights (M(n)=6000-135,000 g mol(-1)) and narrow polydispersities (M(w)/M(n)=1.2-2.6). The catalyst systems are remarkably stable, capable of polymerizing styrene up to 120 degrees C with high activities, while maintaining high syndiotacticity via chain-end control as established by a Bernoullian analysis. Highly effective copolymerization of styrene with ethylene was achieved using neodymium complex 4 (activity up to 2530 kg PS-PE mol(-1) h(-1)) to give true copolymers void of homopolymers with M(n)=9000-152,000 g mol(-1) and narrow polydispersities (M(w)/M(n)=1.2-2.5). The nature of the resultant P(S-co-E) copolymers was ascertained by NMR, size-exclusion chromatography/refractive index/UV, temperature rising elusion fractionation, and differential scanning calorimetry. It is shown that, regardless the amount of ethylene incorporated (1-50 mol %), P(S-co-E) copolymers have a microstructure predominantly made of long highly syndiotactic PS sequences separated by single or few ethylene units. Co-monomers feed and polymerization temperature can be used straightforwardly to manipulate with the physical and mechanical characteristics of the P(S-co-E) copolymers (molecular weights and distributions, co-monomer content, microstructure, T(m), T(g), T(c)).
通过盐复分解反应合成了一系列新型中性烯丙基第3族金属配合物，这些配合物带有ansa桥连的芴基/环戊二烯基配体[[Flu-EMe(2)-(3-R-Cp)]Ln(η(3)-C(3)H(5))(THF)]（E = C，R = H，Ln = Y (2)，La (3)，Nd (4)，Sm (5)；R = tBu，Ln = Y (8)，Nd (9)；E = Si，R = H，Ln = Y (12)，Nd (13)），产率良好。通过元素分析、对抗磁性配合物的核磁共振光谱以及对2、4、9和12的单晶X射线衍射研究对这些配合物进行了表征。一些烯丙基ansa-镧系茂金属，尤其是4，是苯乙烯聚合的有效单组分催化剂，能得到具有低至高分子量（M(n)=6000 - 135,000 g mol(-1)）和窄多分散性（M(w)/M(n)=1.2 - 2.6）的纯间同立构聚苯乙烯（rrrr > 99%）。该催化剂体系非常稳定，能够在高达120℃的温度下以高活性聚合苯乙烯，同时通过伯努利分析确定的链端控制保持高间同立构规整性。使用钕配合物4实现了苯乙烯与乙烯的高效共聚（活性高达2530 kg PS-PE mol(-1) h(-1)），得到不含均聚物的真正共聚物，其M(n)=9000 - 152,000 g mol(-1)且多分散性窄（M(w)/M(n)=1.2 - 2.5）。通过核磁共振、尺寸排阻色谱/折射率/紫外、升温淋洗分级和差示扫描量热法确定了所得P(S-co-E)共聚物的性质。结果表明，无论乙烯的掺入量如何（1 - 50 mol%），P(S-co-E)共聚物的微观结构主要由被单个或少数乙烯单元隔开的长的高间同立构聚苯乙烯序列组成。共聚单体进料和聚合温度可直接用于控制P(S-co-E)共聚物的物理和机械特性（分子量和分布、共聚单体含量、微观结构、T(m)、T(g)、T(c)）。
