光度分析显色试剂的量子化学研究——Ⅳ.变色酸双偶氮氯膦类分子的电子结构与质子化作用

STUDIES ON THE ELECTRONIC STRUCTURE OF CHROMOGENIC REAGENT BASED ON QUANTUM CHEMICAL CALCULATION Ⅳ. The Protonation and Electronic Structure of Molecular of Phosphonazo Analogs

用分光光度法测得了对氯偶氮氯膦、对硝基偶氮氯膦、间硝基偶氮氯膦、间羧基偶氮氯膦及二溴硝基偶氮氯膦等分子的质子化常数;用简单分子轨道理论作量子化学计算,得到该类显色试剂分子的一系列电子结构信息。且进一步讨论了质子化常数与亲电前沿轨道电荷密度这一电子结构参数之间的关系。通过图解法推得间羧基偶氮氯膦的质子化常数理论值,结果和实验值能很好地符合。

This paper reports the results of determing the protonation constants of chlorophosphona zo-PC, chlorophsphxcnazo-pN, chlorophosphonazo-mN, chlorophosphonazo-mK, and DENCPA by spectrophotometric methods. A series of parame(?)ers of electronic structure have been calculated by means of the Huckel. molecular orbital theory. The relation between them has been discussed. Theoretical value of protonation constant of chlorophosphonazo-mK have been deduced by the graphic method. The result is qui(?)e coincident with that of laboratory measurement.