In two consecutive studies the tautomerism in 4-((2-hydroxynaphthalen-1-yl)diazenyl)-3,5-dinitrobenzoic acid and the structurally similar 1-((2-nitrophenyl)diazenyl)naphthalen-2-ol has been considered from viewpoint of theoretical chemistry, UV–Vis spectroscopy and NMR. Although the theoretical data (at M062X level) show that both compounds exist only as a keto tautomer, the experiment proves existence of the enol form. The difference in the results obtained by UV–Vis spectroscopy and NMR requires a deeper consideration and verification of the NMR approach, which is based on using model compounds to provide the NMR signal pattern of individual tautomers.

中文翻译：

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再次解释了4-羧基-2,6-二硝基苯基偶氮羟基萘的互变异构核磁共振和其他方法

在两个连续的研究中，已经考虑了4-（（2-羟基萘-1-基）二氮烯基）-3,5-二硝基苯甲酸和结构相似的1-（（2-硝基苯基）二氮烯基）萘-2-醇的互变异构现象。从理论化学，UV-Vis光谱学和NMR的角度来看。尽管理论数据（在M062X级别）显示这两种化合物仅以酮互变异构体形式存在，但实验证明存在烯醇形式。通过UV-Vis光谱学和NMR获得的结果差异需要更深入地考虑和验证NMR方法，该方法基于使用模型化合物提供单个互变异构体的NMR信号模式。