一种增强大π离域化合物图谱精细结构的制样方法

A Sampling Method for Enhancing Fine Structure of Large π Delocalized Compound Maps

常用的氘代溶剂氘代氯仿(CDCl3)经长期放置时,在光催化作用下发生反应产生DCl,会对大π离域共轭芳基化合物样品的测试产生干扰,出现包状峰、无裂分、积分不准确等现象。为解决此问题,采用干燥碳酸钾(K2CO3)对CDCl3进行预处理,即在CDCl3中加入刚干燥处理的K2CO3,搅拌、振荡或超生一定时间,过滤得到溶液作为氘代溶剂。结果发现,干燥K2CO3处理CDCl3,通过酸碱中和反应,有效去除DCl,使大π离域共轭芳基化合物保持本征态,确保其1H NMR图谱表现出精确的精细结构与积分,表明该制样方法简单易行,可为实际理论和实验教学提供重要补充。

Deuterated chloroform (CDCl3),a commonly used deuterated solvent,reacts under the photocatalysis to produce DCl when left untouched for a long time,which interferes with the testing of largeπdelocalized conjugated aryl compound samples,resulting in inclusion peaks,no cleavage and inaccurate integration.To solve it,dry potassium carbonate (K2CO3) is used to pretreat CDCl3.Specifically,freshly dried K2CO3is added to CDCl3,then stirred,shaken or supernatant for a certain period of time,finally filtered as a deuterated solvent.The results show that CDCl3with dried K2CO3effectively removes DCl through acid-base neutralization reaction without affecting the~1H NMR spectra of largeπdelocalized conjugated aryl compounds.Instead,it makes the~1H NMR spectrum non resolvable.This sampling method not only enhances the fine structure of the spectrum of largeπdelocalized compounds,but also proves simple and feasible,which serves as an important supplement to practical theory and experimental teaching.