Conductivity and Dissociation Constants of Quaternary Ammonium Perchlorates and Picrates in 4-Methyl-pentan-2-one
作者:Sergey T. Goga、Alexander V. Lebed、Nikolay O. Mchedlov-Petrossyan
DOI:10.1021/je9008969
日期:2010.5.13
The dissociation of 14 ionophores, namely, seven symmetrical (C1 to C7) and five asymmetrical quaternaryammonium perchlorates and two tetraalkylammonium picrates (all with linear hydrocarbon chains), in 4-methyl-pentan-2-one was studied at 25 °C (εr = 12.92) using the conductance method. The values of the association constants of the quaternaryammonium cation, Ct+, with ClO4− vary from (7.4 ± 0.3)·103
perchlorate anion to the cetylpyridinium cation. This explains a noticeable difference in the 1H NMR chemical shifts of the hydrogen atoms in the ortho-position (∼0.2 ppm) and the α-methylene group (∼0.1 ppm) of the DMSO solutions of the cetylpyridinium perchlorate and chloride salts micelles. The electronic structure analysis of cetylpyridinium perchlorate and cetylpyridinium chloride in terms of
采用差热分析 (DTA)、X 射线粉末衍射 (XRD) 技术、傅里叶变换红外光谱 (FT-IR) 和1 H 和13 C 核磁共振 (NMR) 光谱合成和表征了十六烷基高氯酸吡啶鎓. 所研究的盐在 100 °C 下完全熔化。DTA和XRD结果表明,在不同温度下合成的高氯酸十六烷基吡啶样品的结晶度不同。已经确定样品的结晶度影响分解温度。最高分解温度(T d = 265 °C) 观察到在 20 °C 结晶的样品。高氯酸十六烷基吡啶鎓在单斜晶系中结晶,晶胞参数a = 20.31 Å,b = 16.20 Å,c = 7.25 Å,β = 95.26°,Z = 4。 根据 DFT 计算,结构中的离子间相互作用的特征在于电子从高氯酸根阴离子转移到十六烷基吡啶鎓阳离子。这解释了十六烷基吡啶鎓高氯酸盐和氯化物盐胶束的 DMSO 溶液的邻位 (~0.2 ppm) 和α-亚甲基 (~0.1 ppm)的氢原子的1