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Synthesis of Chromogenic Crown Ethers and Liquid—liquid Extraction of Alkaline Earth Metal Ions by Yoshiki Katayama; Ryuji Fukuda; Toshiharu Iwasaki; Kazuhide Nita; Makoto Takagi is a Chemistry article available to read on EtoBox.

What is Synthesis of Chromogenic Crown Ethers and Liquid—liquid Extraction of Alkaline Earth Metal Ions about?

New crown ether dyes carrying two pendent anionic side-arms were synthesized for the extraction-spectrophotometry of alkaline earth metal ions. In the extraction of alkaline earth metal ions by these dianionic reagents, size recognition by the crown ether ring was more remarkable than m the case of alkali metal ion extraction by a similar type of monoanionic reagents. Dramatic changes in metal selectivity were observed when the nature of the anionic side-arm was changed while the crown ether skeleton was kept the same. The structure/selectivity relationship is discussed in terms of "chelate" and "intramolecular ion-pair" formation. Typically, when the basicity of the pendent anions was relatively high and a six-membered chelate was structurally possible for the pendent anions and the crown-bound metal, the extraction of calcium was favored by up to a factor of 3000 in the ratio of the Ca/Ba extraction constants for reagents of the diaza-18crown-6 type. In contrast, the reagents which had pendent anions with only poor coordination ability for metal ions seemed to form complexes of the ion-pair type, and calcium ion was lo5 times less extractable than barium ion for the same diaza-18

Who reads Synthesis of Chromogenic Crown Ethers and Liquid—liquid Extraction of Alkaline Earth Metal Ions?

Author

Yoshiki Katayama; Ryuji Fukuda; Toshiharu Iwasaki; Kazuhide Nita; Makoto Takagi

Publisher

Elsevier Science; Elsevier ; Elsevier BV (ISSN 0003-2670)

Published

1988

Language

EN

Field

Chemistry (Physical Sciences)