Anionic polymerization of methyl methacrylate initiated with late transition‐metal halides/organolithium/triisobutylaluminum systems
Anionic polymerization of methyl methacrylate initiated with late transition‐metal halides/organolithium/triisobutylaluminum systems
复制标题
DOI：
10.1002/pola.10737
复制
发表时间：
2003-07
期刊：
影响因子：
--
通讯作者：
E. Ihara;T. Todaka;Kenzo Inoue
中科院分区：
文献类型：
--
作者：
E. Ihara;T. Todaka;Kenzo Inoue
研究了后过渡金属卤化物[MnCl_2、FeCl_2、FeCl_3、CoCl_2、NiBr_2]/有机锂[nBuLi或PhLi]/三异丁基铝（iBu_3Al）体系引发甲基丙烯酸甲酯（MMA）的阴离子聚合。除溴化镍体系外，甲基丙烯酸甲酯（MMA）在0 °C甲苯中聚合均能定量地得到分子量分布窄的高分子量聚甲基丙烯酸甲酯（PMMAs）。基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）分析与FeCl 2，FeCl 3，和CoCl 2的系统获得的PMMA显示，聚合物的氢（H）在两个链端。因此，过渡金属卤化物与有机锂在iBu 3Al存在下的反应应导致过渡金属氢化物[M-H]−的形成，其亲核性足以引发MMA聚合。由于在不存在iBu 3Al的情况下用金属卤化物（FeCl 2、FeCl 3或CoCl 2）/有机锂体系获得的PMMA的MALDI-TOF MS分析证实了由反咬产生的六元环状结构的存在，因此在ω-链末端引入H表明iBu 3Al应防止反咬。而MnCl 2/nBuLi/iBu 3Al引发体系得到的PMMAs在α链端带有H，在ω链端带有六元环状结构。© 2003 Wiley Periodicals，Inc.聚合物科学杂志A部分：聚合物化学41：1962-1977，2003年
Anionic polymerization of methyl methacrylate (MMA) initiated with late transition-metal halides [manganese chloride (MnCl2), iron dichloride (FeCl2), iron trichloride (FeCl3), cobalt chloride (CoCl2), or nickel bromide (NiBr2)]/organolithium [nButyllithium (nBuLi) or phenyllithium (PhLi)]/triisobutylaluminum (iBu3Al) systems is described. Except for the system with NiBr2, the polymerizations of MMA afforded narrow molecular weight distribution poly(methyl methacrylate)s (PMMAs) with high molecular weights in quantitative yields at 0 °C in toluene. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analyses of the PMMAs obtained by the systems with FeCl2, FeCl3, and CoCl2 revealed that the polymers had hydrogen (H) at both chain ends. Accordingly, the reaction of the transition-metal halides with the organolithium in the presence of iBu3Al should result in the formation of transition-metal hydride [M-H]− species, which was nucleophilic enough to initiate the MMA polymerization. Because the presence of a six-membered cyclic structure resulting from backbiting was confirmed from the MALDI-TOF MS analyses of the PMMA obtained with the metal halide (FeCl2, FeCl3, or CoCl2)/organolithium systems in the absence of iBu3Al, the introduction of H at the ω-chain end indicated that iBu3Al should prevent the backbiting. However, the MnCl2/nBuLi/iBu3Al initiating system gave PMMAs bearing H at the α chain end and six-membered cyclic structure at the ω chain end. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1962–1977, 2003