Extractions and spectroscopic studies of various metals with Diglycolamide-Type Tridentate Ligands

Sasaki, Yuji  ; Saeki, Morihisa*; Yoshizuka, Kazuharu*

Three tridentate extractants and three masking reagents including O, N, and S donors have been developed and their properties are compared and discussed. The extractants are termed as tetraoctyl-diglycolamide (TODGA), methylimino-dioctylacetamide (MIDOA) and tetraoctyl-thiodiglycolamide (TDGA(C8)) and masking agents have the same central frame but with short alkyl chain. The results of the present study indicate that TODGA can extract mainly hard acid metals belonging groups 2-4,13-15 in periodic table, MIDOA can extract soft acid metals and oxyanions (groups 5-10, 16), and TDGA can extract soft acid metals (groups 10-11). Some spectrophotometric studies (UV, IR, and NMR) indicate the stoichiometry and effect of donor atoms for metal-complexation. The Hf values, the heat generation during complex formation, obtained by chemical calculation by DFT theory show the reverse-correlation with their extraction ability.