三乙胺与等电子类似结构烷烃的计算红外光谱比较

Comparison of Calculated IR Spectrum of Triethylamine to that of Alkane with Isoelectric and Similar Structure

本研究采用计算化学方法、应用Gaussian03化学软件,研究3-乙基戊烷的中心C原子被N原子取代后成为三乙胺后,三乙胺和3-乙基戊烷红外光谱的区别,并且研究这两种具有等电子类似结构分子的稳定性。通过比较它们的红外谱图得知,C原子被N原子代替以后,三乙胺的C-H红外峰大部分发生蓝移,少数C-H红外峰发生红移;同时,三乙胺红外谱图与3-乙基戊烷红外谱图比较,增加了四个C-N(包括C-N-C)拉伸和剪切红外峰,分别对应在1238.47、1175.40、1085.81和1026.70 cm-1位置上。经分析,3-乙基戊烷的稳定性好于三乙胺。

In the research the computational chemistry method and Gaussian03 software are carried out to investigate,when the central C atom in 3-ethylpentane is replaced by N atom,the difference between the infrared spectrum of triethylamine and that of 3-ethylpentane,and the stability of these two kinds of molecules which have isoelectric and similar Structures.The infrared spectrum of triethylamie is compared to that of 3-ethylpentane,when the central C atom in 3-ethylpentane is replaced by N atom,the most positions of C-H infrared peaks in the Infrared spectrum of triethylamie are blue-shifts and red-shifts are less.For triethylamine,there are four additional C-N（or C-N-C） stretch and scissor vibrational modes,which are corresponding to four infrared absorption peaks at 1238.47,1175.40,1085.81 and 1026.70 cm-1 respectively,comparing to 3-ethylpentane.Based on analysis,it is concluded that 3-ethylpentane is more stable than triethylamine.