acid-base properties, structures, and tautomerism of protonated and free forms of carboxylic acid guanyl hydrazides (acylaminoguanidines) were studied using experimental and theoretical methods. According to the experimental data, guanyl hydrazides are relatively strong bases (pKa 8.1-8.9 in water at 25 °C) in spite of the presence of the electron-withdrawing carbonyl group in their molecules. The results
使用实验和理论方法研究了质子化和游离形式的
羧酸脒酰
肼(酰基
氨基
胍)的酸碱性质、结构和互变异构现象。根据实验数据,尽管分子中存在吸电子羰基,但
胍基酰
肼是相对强的碱(在 25°C 的
水中p K a 8.1-8.9)。NMR光谱、X射线衍射分析和DFT计算的研究结果表明,在极性介质中,游离的
胍基酰
肼主要以两性离子互变异构体(内盐)的形式存在,正电荷定位在质子化
胍部分,负电荷定位在去质子化
胍部分。酰胺基。