Water-soluble sodium hydroxycalix[n]arene-p-sulfonates(Nan1n, n=4, 6 and 8), which were prepared by introducing the sulfonic acid groups into the p-positions of the hydroxyl groups of calix[n] arenes, behaved as a metal ligand even in the acidic solution and formed slightly soluble metal complexes in water with rare earth-, alkali earth- and some other metal ions, such as zirconium(IV), hafnium(IV) and thorium(IV). The composition of the metal complexes with rare-earth metal ions (Ln3+) was found to be NaLn14·mH2O(m=7 - 14), Ln216·mH2O(m=17 - 40) and Ln2H218·mH2O(m=14 - 35), respectively, by the elemental analyses and IR spectra. The effects of the molar ratio of the metal ion to the ligand and the presence of the coexisting anions in the reaction mixture upon the yield of the complex also supported the above composition and indicated that the metal ion in the complex is bound with sulfonate groups of the ligand molecule forming the sulfonate chelate like a salt in property. A series of alkali earth metal ions(M2+) such as Ca2+, Sr2+ and Ba2+ also formed metal complexes having the similar molecular formulas, M214·mH2O(m=5 - 10), M316·mH2O(m=5 - 22) and M418·mH2O(m=6 - 20), respectively. On the other hand, tetravalent metal ions such as Zr(IV), Hf(IV) and Th(IV) formed the complexes in which both sulfonate groups attached at the upper rim and deprotonated hydroxyl groups attached at the lower rim of the ligand coordinated to a metal ion in the complex.
|Number of pages||1|
|Journal||Nippon Kagaku Kaishi / Chemical Society of Japan - Chemistry and Industrial Chemistry Journal|
|Publication status||Published - 1996|
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)