若丹宁偶氮同系物是七十年代发展起来的一类新光度显色试剂。这类试剂与贵金属离子的显色反应具有很高的灵敏度和选择性。到目前为止,Саввин等人已发表了20余篇关于这类试剂的合成、性质和分析应用方面的研究报导。已研究过的这类化合物有:若丹宁偶氮化合物、硫代若丹宁偶氮化合物、3-取代若丹宁偶氮化合物和硫代丙酰若丹宁偶氮化合物。它们的结构通式如下:A.若丹宁偶氮化合物 If rhodanine azo homologue is developed in the seventies a new class of photometric color reagent. Such reagents and precious metal ions color reaction with high sensitivity and selectivity. So far, Саввин and others have published more than 20 articles on the synthesis, properties and analytical applications of these reagents. Such compounds that have been studied are: rhodanine azo compound, thio rhodanine azo compound, 3-substituted rhodanine azo compound, and thiopropionyl rhodanine azo compound. Their structural formula is as follows: A. If the tannin azo compounds