| 分光光度法研究镧与间乙酰基偶氮氯膦(CPAmA)配合物的形成反应 |
| SPECTROPHOMETRIC STUDY ON LANTHANUM-CHLOROPHOSPHONAZO-m-COCH3 (CPAmA) COMPLEX |
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| 摘要: 本文用分光光度法研究了间乙酰基偶氮氯膦试剂在水溶液中的离解作用和质子化作用;镧与间乙酰基偶氮氯膦配合物的组成和β型配合物形成反应的条件和动力学特征,并测定了α型配合物的积累稳定常数 |
| 关键词: 镧 间乙酰基偶氮氯膦 分光光度法 双偶氮衍生物 |
| 基金项目: 中国科学院科学基金资助课题 |
| Abstract: The properties of chlorophosphonazo-m-COCH3 (CPAmA) and the composition and stability of a-type complex of lanthanum with this reagent toEether with the formation reaction of the β-type complex were studied in this paper. The results of this study showed that the wave length of maximum absorption shifts toward the longer wave length as the pH of reagent solution turned highed. The negative logarithm valuues of dissociation constants are pK= 0.39, pK2=1.12, pK3=2.74, pK4=6.79, pK5 =9.73, pK6 = 11.46(546nm). The protonation constant of the reagent in acidic medium is lgKp =-2.45(546nm) and-2.43(662nm).The formation of a-type complex of La-CPAmA has a relatively wide metal/reagent mole ratio and wide pH range, and takes place quickly. The complex is also very stable. But the β-type complex is formed at the mole ratio of La/CPAmA1.5-2.0 and pH range 1.85-2.10. The reaction takes place after certain period of time, but precipitate forms when the solution is allowed to stand for too long. The B-type complex is formed from a-type complex. Kinetic studies indicates that this is a first order reaction, its half time being 76.5 minutes.The composition of the La/CPAMA complex, as determinded by the methods of continuous variation, slope ratic and equilibrium shift, shows that the metal to-ligand ratio is 1:3; the equilibrium shift method also gives evidence for the existence of both 1:1 and 1:2 complexes.The 1:3 complex existed in the acidic medium with excess of reagent has an accumulation stability constant logβs of 50.07. |
| Keywords: lanthanum chlorophosphoa20-in-COCH3 spectrophotometry |
| 投稿时间：1985-09-21 |
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| 赵泓,俞向东,朱传征,沈中平,徐钟隽.分光光度法研究镧与间乙酰基偶氮氯膦(CPAmA)配合物的形成反应[J].无机化学学报,1986,2(1):78-86. |
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