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首页> 外文期刊>Organometallics >d~0/f~n-Mediated Ring-Opening Ziegler Polymerization (ROZP) and Copolymerization with Mono- and Disubstituted Methylenecyclopropanes. Diverse Mechanisms and a New Chain-Capping Termination Process
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d~0/f~n-Mediated Ring-Opening Ziegler Polymerization (ROZP) and Copolymerization with Mono- and Disubstituted Methylenecyclopropanes. Diverse Mechanisms and a New Chain-Capping Termination Process

机译：d〜0 / f〜n介导的开环齐格勒聚合（ROZP）以及与单或二取代的亚甲基环丙烷的共聚。多种机制和新的封顶终止过程

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The mono- and disubstituted methylenecyclopropane derivatives 2-phenyl-l-methylene-cyclopropane (A) and 7-methylenebicyclo[4.1.0]heptane (B) have been successfully implemented in ring-opening Ziegler polymerization. Homogeneous ethylene+2-phenyl-l-methylenecyclopropane (A) random copolymerizations are mediated efficiently by the single-site catalysts Cp_2ZrMe~+B(C_6F_5)_4~-, [Cp_2LuH]_2, [Cp_2SmH]_2, and [Cp_2YH]_2 (Cp-C_5Me_5) to produce a copolymer (C) with A enchained in a ring-opened fashion. Single-site coordinative polymerization of 7-methylenebicyclo[4.1.0]heptane (B) proceeds via either ring-opened or ring-unopened pathways. In the presence of Cp_2ZrMe~+ MeB(C6F_5)_3~- at 0degC, B undergoes polymerization to afford the insoluble, ring-unopened homopolymer D, which was characterized by CPMAS NMR, DSC, elemental analysis, FTIR, TGA, and XRD. The melting point of polymer D lies above its decomposition temperature (>300degC). Random copolymerizations of B and ethylene mediated by Cp_2ZrMe~+MeB(C_6F_5)_3~- at room temperature result in polymer E, a polyethylene capped by a ring-opened B fragment. The formation of B-capped polymer E is a consequence of a new chain transfer mechanism, as evidenced by a linear relationship between M_n and [B]~(-1). The rate constant for insertion of ethylene is approx25 x greater than the rate constant for insertion of monomer B into the metal-alkyl bond. Random copolymers (F) of ring-opened B and ethylene are produced when the catalysts Me_2Si(Me_4C_5)(~tBuN)-ZrMe_2, Me_2Si(Me_4C_5)(~tBuN)TiMe_2 (activated by either (C_6H_5)_3C~+ B(C_6F_5)_4~- or B(C_6F_5)_3), and [Cp_2LuH]_2 are employed.
机译：单和二取代的亚甲基环丙烷衍生物2-苯基-1-亚甲基-环丙烷（A）和7-亚甲基双环[4.1.0]庚烷（B）已成功地用于开环齐格勒聚合中。单中心催化剂Cp_2ZrMe〜+ B（C_6F_5）_4〜-，[Cp_2LuH] _2，[Cp_2SmH] _2和[Cp_2YH] _2有效地介导均相乙烯+ 2-苯基-1-亚甲基环丙烷（A）无规共聚（Cp-C_5Me_5）以产生具有以开环方式链合的A的共聚物（C）。 7-亚甲基双环[4.1.0]庚烷（B）的单中心配位聚合通过开环或开环途径进行。在0°C下存在Cp_2ZrMe〜+ MeB（C6F_5）_3〜-的情况下，B进行聚合，得到不溶的，未开环的均聚物D，其特征在于CPMAS NMR，DSC，元素分析，FTIR，TGA和XRD表征。聚合物D的熔点高于其分解温度（＞ 300℃）。在室温下，Cp_2ZrMe〜+ MeB（C_6F_5）_3〜-介导的B与乙烯的无规共聚生成聚合物E，该聚合物由开环的B片段封端。 B封端的聚合物E的形成是新的链转移机制的结果，M_n与[B]〜（-1）之间的线性关系证明了这一点。乙烯插入的速率常数大约比单体B插入金属-烷基键的速率常数大25倍。当催化剂Me_2Si（Me_4C_5）（〜tBuN）-ZrMe_2，Me_2Si（Me_4C_5）（〜tBuN）TiMe_2（被（C_6H_5）_3C〜+ B（C_6F_5活化）时，会生成开环B和乙烯的无规共聚物（F） ）_4〜-或B（C_6F_5）_3）和[Cp_2LuH] _2被使用。

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