2,5-Dihydro-1H-imidazole-Based Nitroxides as Prospective Mediators in Living Radical Polymerization
作者:Dmitry Zubenko、Igor Kirilyuk、Galina Roshchupkina、Irina Zhurko、Vladimir Reznikov、Sylvain R. A. Marque、Elena Bagryanskaya
DOI:10.1002/hlca.200690218
日期:2006.10
parameters of reactions modelling the 2,5-dihydro-1H-imidazole 1-oxide mediated living polymerization of acrylates. The homolysis rate constants of alkoxyamines based on five nitroxides were measured by EPR spectroscopy at different temperatures. The recombination rate constants kc between the corresponding alkyl radicals and the nitroxides were measured by means of laser flash photolysis. The time-resolved
应用了许多光谱方法来获得模拟2,5-二氢-1 H-咪唑1-氧化物介导的丙烯酸酯活性聚合反应的动力学参数。通过EPR光谱法在不同温度下测量基于五种氮氧化物的烷氧基胺的均解速率常数。重组率常数k c借助于激光闪光光解法测量相应的烷基和氮氧化物之间的比值。时间分辨的化学诱导的动态核极化(TR-CIDNP)实验表明歧化在重组反应中的贡献可忽略不计。另外,在NMR探针中烷氧基胺的热分解显示出没有从相应的烷氧基胺分子内消除羟胺。动力学参数分析表明,2,5-二氢-1 H-咪唑1-氧化物型自由基是丙烯酸和甲基丙烯酸酯活性聚合的有前途的介质。