日本分析化学会 Acta Medica Okayama 0910-6340 5 2 1989 Liquid-Liquid Distribution Behavior of Ion Association Complexes of Dihalogenocuprate(I) Anions with Azo-Dye Cations as Counter Ions 195 200 EN Koichi Yamamoto Shoji Motomizu The solvent extraction of ion association complexes of dihalogenocuprate(I) ions CuX(2)(-)(X-=chlorideb,r omide and iodide ions), with 4-(4-diethylaminophenylazo)-N-alkylpyridiniumc ations (azo-dye cations) is described: the alkyl groups of the azo-dye cations were methyl, ethyl and propyl groups. The extraction constants (K(ex)) for the ion association complexes of CuX(2)(-) and X(-) with these three azo-dye cations between an aqueous phase and several organic phases (chloroform, chlorobenzene, benzene and toluene) were determined. The extractabilities of CuX2 and X(-) were in the orders CuCl(2)(-)<CuBr(2)7<Cul(2)(-), and Cl(-)(Br(-)<I(-) respectively:t he differences in log K(ex) between two successive ions averaged about 1.2 and 1.3 for CuX(2)(-) and about 1.2 and 1.9 for X(-). In all of the ion association complexes examined, the order of the values of the extraction constants was chloroform>chlorobenzene>benzene>toluene. The difference in the value of log K(ex) between chloroform and chlorobenzene for CuX(2)(-) was much smaller than that for X(-) while between other solvents the differences in log K(ex) values for CuX(2)(-) and t were almost the same. From the extraction constants obtained, some possible extraction systems for a spectrophotometry for copper are predicted: they include one using chlorobenzene, the methyl derivative of the azo-dye, and iodide ion and one using chlorobenzene, the propyl derivative of the azo-dye and bromide ion. No potential conflict of interest relevant to this article was reported.