Abstract: | 2-Bis(carboxymethyl)-amino-5-hydroxy-terephthalic Acid as an Ambifunctional Ligand in Iron(III) Complexes From steric reasons the anthranilic acid -N,N-diacetic acid group and the salicylic acid group of 2-bis(carboxymethyl)-amino-5-hydroxy-terephthalic acid (H5C) cannot coordinate to the same central atom. With iron(III) H5C forms the mononuclear complex (HC)Fe(OH)2?, the central atom is fixed to the anthranilic acid N,N-diacetic acid group. In a weak acid medium (HC)Fe(OH)2? is converted into the binuclear species (HC)Fe(C)Fe(OH)4? which is of a deep red colour. In this complex the anion C5?has the function of a bridging ligand coordinating both by the anthranilic acid-N,N-diacetic acid group and by the salicylic acid group. The complex formation in the ternary system iron(III)/nitrilo triacetic acid/5-sulfo salicylic acid may be used as model for the dimerisation of the anion (HC)Fe(OH)2?. |