Ten 4,4'-disubstituted bis(arenesulfon)imides of the general formula XC6H4SO2NHSO2C6H4X have been synthesized and their structures confirmed by their 1H NMR spectra. Elemental analyses are presented for the compounds not yet described. The dissociation constants of these model substances have been measured potentiometrically in pyridine, dimethylformamide, methanol, ethanol, propylene carbonate, acetone, acetonitrile, 1,2-dichloroethane and tetramethylene sulfone. The pKHA values obtained have been correlated with three sets of the Hammett substituent constants and the results have been used to discuss the solvent and substituent effects on the dissociation of the compounds studied. Sulfonimides with electron-acceptor substituents behave as rather strong acids in some solvents (pyridine, dimethylformamide, methanol and ethanol), whereas normal substituent dependences are found in other solvents. The experimental data have also been interpreted with the help of the statistical methods based on latent variables. From the calculations it follows that only the first principal component, which correlates well with the substituent constant sets adopted, is statistically significant in describing the substituent effect on the acid-base process studied.
已合成了十种一般公式为XC
6H
4SO
2NHSO
2C
6H
4X的4,4'-二取代双(
芳烃磺酰)
亚胺,并通过它们的1H核磁共振谱确认了它们的结构。对尚未描述的化合物进行了元素分析。这些模型物质的解离常数已在
吡啶、二甲基甲酰胺、
甲醇、
乙醇、
丙烯碳酸酯、
丙酮、
乙腈、
1,2-二氯乙烷和
四亚甲基砜中电位测定。获得的p
KHA 值已与三组Hammett取代基常数相关联,并利用结果讨论了溶剂和取代基对所研究化合物解离的影响。在某些溶剂中(如
吡啶、二甲基甲酰胺、
甲醇和
乙醇),具有电子受体取代基的磺
酰亚胺表现为相当强的酸,而在其他溶剂中发现了正常的取代基依赖性。实验数据还通过基于潜在变量的统计方法进行了解释。计算结果表明,仅第一个主成分与所采用的取代基常数集相关,对所研究的酸碱过程的取代基效应具有统计学意义。