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1,2‐FDTA: A Ferrocene‐Based Redox‐Active EDTA Analogue with a High Ca 2+ /Mg 2+ and Ca 2+ /Sr 2+ Selectivity in Aqueous Solution
Author(s) -
Plenio Herbert,
Burth Dirk,
Vogler Raphael
Publication year - 1997
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19971301008
Subject(s) - chemistry , redox , selectivity , potentiometric titration , inorganic chemistry , aqueous solution , metal , metal ions in aqueous solution , alkaline earth metal , cyclic voltammetry , qualitative inorganic analysis , ferrocene , nuclear chemistry , ion , electrochemistry , electrode , organic chemistry , catalysis
1, 2‐Ferrocenemethylenediyldiamino tetraacetate (1,2‐FDTA) is a redox‐active relative of EDTA and was synthesized in the reaction of 1,2‐bis(chloromethyl)ferrocene with iminodiacetate methyl ester followed by cleavage of the ester with methanolic KOH. Potentiometric determination of the stability constants of the complexes of 1,2‐FDTA with the alkaline earth metal ions showed this ligand to display a higher Ca 2+ /Mg 2+ and Ca 2+ /Sr 2+ selectivity (Ca 2+ log K = 6.56, Mg 2+ log K = 4.65, Sr 2+ log K = 3.32) than EDTA itself. The redox potential of 1,2‐FDTA‐Ca 2+ determined in aqueous solution by cyclic voltammetry was found to be anodically shifted by +50 mV with respect to that of the calcium free complex. Consequently the redox‐inactive calcium can be determined electrochemically in aqueous solution with a high selectivity with respect to the other alkaline earth metal ions.