The living anionic polymerization of activated aziridines: a systematic study of reaction conditions and kinetics
The living anionic polymerization of activated aziridines: a systematic study of reaction conditions and kinetics
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DOI：
10.1039/c7py00436b
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发表时间：
2017-05
影响因子：
4.6
通讯作者：
E. Rieger;Tassilo Gleede;Katja Weber;A. Manhart;M. Wagner;F. Wurm
中科院分区：
文献类型：
--
作者：
E. Rieger;Tassilo Gleede;Katja Weber;A. Manhart;M. Wagner;F. Wurm
“活的种族”——阴离子聚合的聚合动力学在很大程度上取决于溶剂极性和生长链末端的反应性。碳水化合物和氧阴离子聚合在大学实验室和工业水平上都得到了控制，然而，没有关于叠氮-阴离子聚合的系统报道。采用实时1H NMR技术研究了2-甲基- n -甲酰基氮吡啶（MsMAz）和2-甲基- n -甲酰基氮吡啶（TsMAz）两种活性氮吡啶的聚合反应。该技术允许在不同条件下（温度、溶剂、引发剂和反离子变化）精确监测聚合过程中单体的消耗。根据实验数据，计算并分析了传输速率常数kp。在不同温度（20、50和100℃）下监测MsMAz的聚合。温度的升高提高了聚合的速度，但保持了活性。此外，还考察了不同溶剂对聚合速度的影响，证明溶剂溶剂如DMSO和DMF是最快的溶剂。比较了两种不同的引发剂N，N ' -（1,4-苯基双（亚甲基））二甲基磺酰胺（BnBis(NHMs)）的钾盐，N ' -（1,4-苯基双（亚甲基））二甲基磺酰胺（BnNHMs），氮嘧啶AROP的第一双功能引发剂和N-苄基磺酰胺（BnNHMs）。反离子Li+， Na+， K+和Cs+（分别由双（三甲基硅基）酰胺盐产生）的变化证明了两种单体与所有反离子的成功聚合。Cs+ > Li+ > Na+ > K+的顺序略有不同，这与环氧化物的AROP形成强烈对比，显示出强烈的基因依赖性动力学曲线。这允许使用商业上可用的引发剂，如用于合成PAz的BuLi。有了这些结果，偶氮阴离子聚合可以作为阴离子聚合家族中有价值的工具，用于在多种条件下制备结构多样的聚磺胺和多胺，同时保持其活性行为。
“A living race” – polymerization kinetics of anionic polymerizations depends strongly on the solvent polarity and reactivity of the growing chain end. Both the carb- and oxyanionic polymerization is under control at the university lab and on the industrial level, however, no information for the aza-anionic polymerization of aziridines has been reported systematically. This work studies the polymerization of two activated aziridines (2-methyl-N-mesylaziridine (MsMAz) and 2-methyl-N-tosylaziridine (TsMAz)) by real-time 1H NMR spectroscopy. This technique allows monitoring the consumption of the monomer precisely during the polymerization under different conditions (temperature, solvent, initiator and counter-ion variation). From the experimental data, propagation rate constants (kp) were calculated and analyzed. The polymerization of MsMAz was monitored at different temperatures (20, 50, and 100 °C). The increase of temperature increases the speed of polymerization, but keeps the living behavior. Furthermore, the influence of different solvents on the polymerization speed was examined, proving solvating solvents such as DMSO and DMF as the fastest solvents. Two different initiators, the potassium salts of N,N′-(1,4-phenylenebis(methylene))dimethanesulfonamide (BnBis(NHMs)), the first bifunctional initiator for the AROP of aziridines, and of N-benzyl-sulfonamide (BnNHMs) were compared. The variation of the counter ions Li+, Na+, K+, and Cs+ (generated from the respective bis(trimethylsilyl)amide salts) proved successful polymerization of both monomers with all counter ions. Slight variations have been detected in the order: Cs+ > Li+ > Na+ > K+, which is in strong contrast for the AROP of epoxides, shows a strong gegenion-dependent kinetic profile. This allows the use of commercially available initiators, such as BuLi for the synthesis of PAz. With these results in hand, the azaanionic polymerization can be used as a valuable tool in the family of anionic polymerization for the preparation of structurally diverse polysulfonamides and polyamines under a broad variety of conditions, while maintaining the living behavior.