Hydrogen bonding and the inductive effect in crystalline and solution phases of hexylamine:LiCF3SO3 and Dipropylamine:LiCF3SO3: application to branched poly(ethylenimine).
Hydrogen bonding and the inductive effect in crystalline and solution phases of hexylamine:LiCF3SO3 and Dipropylamine:LiCF3SO3: application to branched poly(ethylenimine).
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DOI：
10.1021/jp052965g
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发表时间：
2005-11
期刊：
影响因子：
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通讯作者：
N. Rocher;R. Frech;M. Khan
中科院分区：
文献类型：
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作者：
N. Rocher;R. Frech;M. Khan
利用拉曼光谱和红外光谱研究了LiCF(3)SO(3)在伯胺己胺和仲胺二丙胺溶液中的氢键性质和阳离子诱导效应。将纯己胺与溶解在CCl中的己胺(4)进行比较，发现纯己胺对称拉伸模式的拉曼能带最大值nu(s)（NH(2)）来源于没有氢键相互作用的分子。在己胺或二丙胺中加入LiCF(3)SO(3)可以通过氢键断裂和阳离子感应效应改变溶剂NH伸展模式的频率。红外光谱和拉曼光谱的比较允许（在某种程度上）分离这两种效应。在这些研究中，发现了六胺：LiCF(3)SO(3)和二丙胺：LiCF(3)SO(3)的结晶化合物，并通过单晶x射线衍射技术对其结构进行了解析。这些晶体的振动光谱和阳离子-溶剂相互作用的详细结构知识补充了溶液相的类似光谱研究。用含有溶解LiCF(3)SO(3)的己胺和二丙胺溶液模拟了支化聚乙亚胺（BPEI）与LiCF(3)SO(3)配合的阳离子聚合物和氢键相互作用。具体来说，锂离子与BPEI中伯胺和仲胺的相互作用分别通过与己胺和二丙胺的溶液研究来模拟。六胺体系的分析特别有用，因为BPEI的伯胺基团在光谱的NH拉伸区占主导地位。
Raman and infrared spectroscopy were used to study the nature of hydrogen bonding and the cation inductive effect in solutions of LiCF(3)SO(3) dissolved in hexylamine, a primary amine, and dipropylamine, a secondary amine. Comparison of pure hexylamine and hexylamine dissolved in CCl(4) established that the Raman band maximum of the symmetric stretching mode, nu(s)(NH(2)), in pure hexylamine originates in molecules undergoing no hydrogen bonding interactions. The addition of LiCF(3)SO(3) to hexylamine or dipropylamine shifts the frequencies of the solvent NH stretching modes by two effects: the breaking of hydrogen bonds and the cation inductive effect. Comparison of the infrared and Raman spectra allows (to some degree) the separation of these two effects. During these studies, crystalline compounds of hexylamine:LiCF(3)SO(3) and dipropylamine:LiCF(3)SO(3) were discovered, and their structures were solved by single-crystal X-ray diffraction techniques. Vibrational spectra of these crystals and detailed structural knowledge of the cation-solvent interactions complement analogous spectroscopic studies of the solution phases. The cation-polymer and hydrogen bonding interactions of branched poly(ethylenimine) (BPEI) complexed with LiCF(3)SO(3) were modeled by the solutions of hexylamine and dipropylamine containing dissolved LiCF(3)SO(3). Specifically, lithium ion interactions with the primary and secondary amine groups in BPEI were modeled by the solution studies with hexylamine and dipropylamine, respectively. The analysis of the hexylamine system was particularly useful because the primary amine group of BPEI dominates the NH stretching region of the spectrum.