化学学报 ›› 2002, Vol. 60 ›› Issue (10): 1747-1753. 上一篇    下一篇

研究论文

DMF-H_2O缔合体系的~1HNMR研究

雷毅;李浩然;朱龙华;韩世钧   

  1. 浙江大学化学系,杭州(310027);中国计量学院生命科学学院,杭州(310034)
  • 发布日期:2002-10-15

~1H NMR Studies of DMF-H_2O Association System

Lei Yi;Li Haoran;Zhu Longhua;Han Shijun   

  1. Department of Chemistry, Zhejiang University,Hangzhou(310027)
  • Published:2002-10-15

DMF水溶液是一种生物分子水溶液的简单生化模型。测量了DMF-H_2O体系不同 温度下全浓度范围的~1H NMR数据,对体系中的缔合情况进行了讨论,基于H_2O, H_2O·DMF, (H_2O)_2和(DMF)_2·H_2O的缔合平衡建立了化学缔合模型,采用最 小二乘法拟合实验数据,联合遗传算法和Levenberg-Marquardt算法对模型参数进 行全局寻优求解得不同温度的缔合平衡常数K,再根据不同温度的K求得缔合平衡的 ΔH和ΔS。为了更好地理解DMF水溶液中分子间的相互作用,还测量了298 K下DMF- CCl_4和DMF-BuOH体系全浓度范围的~1H NMR数据作为比较,结合NMR的基本原理对 各DMF溶液体系~1H NMR的实验现象进行了分析和解释,认为水溶液的特殊结构、氢 键和DMF酰胺基的共轭体系是影响DMF-H_2O体系~1H NMR的主要因素。

关键词: 二甲基甲酰胺, 水, 质子磁共振谱法, 缔合

Dimethylformamide (DMF) aqueous solution is a kind of simple biochemical model of biological molecular aqueous solutions. In this paper, ~1H NMR of DMF-H_2O system was measured at different temperatures to discuss molecular interactions in the mixtures. The association system was modeled on the equilibrium among H_2O, H_2O· DMF, (H_2O)_2 and (DMF)_2·H_2O and calculated by nonlinear least- square fitting. Association equilibrium constant K and the corresponding ΔH and ΔS were obtained by combined GA and levenberg- marquardt algorithm. In addition, DMF-CCl_4 and DMF-BuOH systems were also studied in order to further understand the nature of interactions in DMF-water mixture. Some peculiar phenomena were found and considered to be mainly caused by the special structure of liquid water, the hydrogen-bonding interactions and the conjugate system of amide.

Key words: DIMETHYLFORMAMIDE, WATER, 1HNMR, ASSOCIATION

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