Esters of 2-bromo-2-methylpropanoate of poly(oxyalkylene) polymers such as poly(ethylene glycol) or α-methyl poly(ethylene glycol) were prepared in high yields and characterized by spectroscopic and chromatographic methods (NMR, FT-IR, mass spectroscopy and SEC). The halogen chain-end group in the poly(oxyalkylene) bromine-terminated esters was characterized by MALDI-TOF MS. The effect of the solvents (methanol or tetrahydrofuran) and the cationic agents such as silver trifluoroacetate (AgTFA), silver trifluoromethanesulfonate (AgTFS) and sodium trifluoroacetate (NaTFA) on the mass spectra was studied. Analysis of the mass spectra demonstrated that the analyte was transformed to unsaturated (elimination), alkoxy or hydroxyl end-groups (substitution) molecules when silver cationic agents were used; these results were also supported by 1H NMR study. When sodium salt was used as a cationic agent, well-defined bromine-terminated macromolecules were successfully determined through MALDI-TOF MS. Well-characterized esters of 2-bromo-2-methylpropanoate of poly(oxyalkylene) polymers could be used as ATRP macroinitiators for the synthesis of a variety of polymeric architectures of interest as drug delivery bioconjugates.

中文翻译：

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通过 MALDI-TOF 光谱评估聚（氧化烯）聚合物的 2-溴-2-甲基丙酸酯中的卤素链端官能度

以高收率制备了聚（氧化烯）聚合物（如聚（乙二醇）或 α-甲基聚（乙二醇）的 2-溴-2-甲基丙酸酯），并通过光谱和色谱方法（NMR、FT-IR、质谱和SEC）。聚（氧化烯）溴封端酯中的卤素链端基团通过 MALDI-TOF MS 进行表征。研究了溶剂（甲醇或四氢呋喃）和阳离子试剂如三氟乙酸银 (AgTFA)、三氟甲磺酸银 (AgTFS) 和三氟乙酸钠 (NaTFA) 对质谱的影响。质谱分析表明，当使用银阳离子试剂时，分析物转化为不饱和（消除）、烷氧基或羟基端基（取代）分子；这些结果也得到了 1H NMR 研究的支持。当钠盐用作阳离子试剂时，通过 MALDI-TOF MS 成功确定了明确定义的溴封端大分子。表征良好的聚（氧化烯）聚合物的 2-溴-2-甲基丙酸酯可用作 ATRP 大分子引发剂，用于合成各种感兴趣的聚合物结构作为药物递送生物缀合物。