Complex formation reactions of heavier rare earths with meta-acetyl-chlorophosphonazo (CPAmA)

• Published in: Inorganica Chimica Acta Vol. 134; no. 1; pp. 159 - 163
• Main Authors: Hong, Zhao, Chuan-Zheng, Zhu, Rong-Ming, Cheng, Jing-Lin, Wang, Chung-Gin, Hsu
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 02.11.1987; Elsevier Science
• Subjects: Chemistry; Coordination compounds; Exact sciences and technology; Inorganic chemistry and origins of life; Preparations and properties; Azo compound; Preparation; Bicyclic compound; Organic ligand; Visible spectrum; Stability constant; Kinetics; Lanthanide Complexes; Trivalent metal Complexes; Condensed benzenic compound; Phosphorus Organic compounds; Acidic solution
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/S0020-1693(00)84472-2

In acidic medium, heavier rare earths (RE) form 1:3 α-type complexes with CPAmA in excess of reagent. Under certain conditions, each of the α-type complexes is transformed to a β-type complex with an absorption peak at about 713 nm. The transformation reaction is a list-order reaction which depends on the concentrations of reactants, mole ratio of RE/CPAmA, acidity and the standing time of the solution. The stability constants and molar absorptivities of α-type complexes of RE-CPAmA decrease with the increase of the atomic numbers of heavier rare earths. The rate constants and half-life periods of their β-complex formation reactions are also dependent on their atomic numbers.