烟碱与苯甲酸的相互作用研究

Study on the interaction of nicotine and benzoic acid

【目的】探究烟碱与苯甲酸是否可结合形成稳定的复合物。【方法】通过Job’s Plot方法、核磁共振氢谱(1H NMR)、红外光谱、等温滴定量热法(ITC)以及理论计算确定了两者间的相互作用方式。【结果】(1)通过Job’s Plot方法测定了烟碱与苯甲酸的结合比例为1:1。(2)通过核磁共振氢谱及红外光谱确定了烟碱与苯甲酸之间存在相互作用力,确定了两者的结合方式。(3)运用等温滴定量热法再次验证了烟碱与苯甲酸的结合比例,测定了两者结合过程中的热力学数据(ΔH=-26.8 KJ/mol;ΔG=-33.99 KJ/mol;ΔS=24.12 J/mol•K)及结合常数(Ka=9.021×10^5 M^-1)。(4)通过理论计算得出两者的结合能E=-18.64 Kcal/mol。【结论】烟碱与苯甲酸之间存在较强的结合力,可以结合形成1:1的复合物,结合过程是自发的放热过程,复合物拥有更高的热解温度。

[Objective]This paper aims to explore whether nicotine can bind to benzoic acid to form a stable complex.[Methods]The binding manner was confirmed by Job’s Plot method,^1H NMR,FT-IR,ITC and molecular modeling calculation.[Results]1)The binding ratio of nicotine and benzoic acid was confirmed to be 1:1 by Job’s Plot method;2)The binding manner was further confirmed by 1H NMR&FT-IR.3)Thermodynamic data(ΔH=﹣26.8 KJ/mol;ΔG=﹣33.99 KJ/mol;ΔS=24.12 J/mol•K)and association constant(Ka=9.021×10^5 M^-1)were obtained by ITC.4)Binding energy(E=﹣18.64 Kcal/mol)was given by molecular modeling calculation.[Conclusion]The test data showed that nicotine and benzoic acid can form a stable complex with a binding ratio of 1:1,which has a higher decomposition temperature.