Controlled isomerization polymerization of olefins, cycloolefins, and dienes
Controlled isomerization polymerization of olefins, cycloolefins, and dienes
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DOI：
10.1016/j.polymer.2015.09.077
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发表时间：
2016-01
期刊：
影响因子：
4.6
通讯作者：
Daisuke Takeuchi;K. Osakada
中科院分区：
文献类型：
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作者：
Daisuke Takeuchi;K. Osakada
本文介绍了钯催化二烯烃、环戊烯和烯基环己烷异构化聚合的研究进展。钯与二亚胺配体的配合物可促进功能化1，6-二烯的可控环聚合，得到含有重复反式-1，2-双（亚甲基）环戊烯单元的聚合物。二烯与乙烯、α-烯烃、环戊烯等烯烃共聚，得到含五元环的聚合物。7-烷基-1，6-二烯在Pd催化剂作用下的聚合反应不仅发生了环化反应，而且还发生了链行走反应，聚合物中含有1，2-反式亚环戊基单元，并沿聚合物链被低聚亚甲基间隔基沿着隔开。含1，6-二烯结构的三烯经双环化异构化聚合得到两个环戊烯单元直接连接或通过低聚亚甲基间隔基连接的聚合物。聚合物中亚环戊基单元的密度和分布可以通过改变单体来精确控制。4-烷基环戊烯在钯配合物作用下聚合，得到了由1，3-反式环戊烯单元和低聚亚甲基间隔基组成的聚合物。具有假C2对称结构的钯配合物可使环戊烯等规聚合。4-烷基环戊烯的等规聚合物具有液晶性。在钯催化剂作用下，烯基环己烷的异构化聚合导致聚合物具有高熔点，这是由于1，4-反式亚环己基单元的有序排列引起的。尽管1，1-二取代烯烃的反应性一般较低，但在Pd催化剂存在下，亚甲基环己烷的均聚也顺利进行。
This article features recent studies on Pd-catalyzed isomerization polymerization of dienes, cyclopentenes and alkenylcyclohexanes. Pd complexes with diimine ligands promote controlled cyclopolymerization of functionalized 1,6-dienes to afford the polymers with repeatingtrans-1,2-bis(methylene)cyclopentylene units. The dienes copolymerize with various olefins, such as ethylene,α-olefin, and cyclopentene, to yield the polymers containing thetrans–fused five membered rings. The polymerization of 7-alkyl-1,6-dienes by the Pd catalysts involves stereoselective cyclization as well as chain-walking, and the produced polymers contain 1,2-trans-cyclopentylene units separated by oligomethylene spacer along the polymer chain. Trienes with 1,6-diene moieties undergo double cyclizative isomerization polymerization to give the polymers with two cyclopentylene units connected directly or by oligomethylene spacer. The density and distribution of the cyclopentylene units in the polymer can be accurately controlled by changing the monomer. Polymerization of 4-alkylcyclopentenes by the Pd complex, produces the polymers composed of 1,3-trans-cyclopentylene units and oligomethylene spacer. The Pd complexes with pseudo-C2symmetrical structure bring about isospecific polymerization of the cyclopentenes. The isotactic polymers of 4-alkylcyclopentene show liquid crystalline properties. Isomerization polymerization of alkenylcyclohexanes by the Pd catalysts leads to the polymers with high melting point caused by regulated alignment of 1,4-trans-cyclohexylene units. Homopolymerization of methylenecyclohexanes also proceeds smoothly in the presence of the Pd catalyst in spite of general low reactivity of the 1,1-disubstituted olefins.