Ethylenediaminetetraacetic acid H4EDTA

The only compounds with this type of ligand appear to be the hydrated neptunium(V) complexes with ethylenediaminetetraacetic acid (H4edta), (Np02)2H2(edta)-5H20 and [Co(NH3)6]Np02(edta) -3H20. 

From 1967 to 1969, Kerr published a series of papers on the question of thermal and hydrothermal stabilities of sodium and hydrogen zeolite Y (22-26). These studies indicated that upon removal of about one-third of the aluminum from zeolite Y, using ethylenediaminetetraacetic acid (H4EDTA), the thermal and hydrothermal stabilities were much enhanced. This was observed for both sodium (23) and hydrogen (25) forms of the zeolite. The latter was prepared by careful calcination of an ammonium zeolite from which about 30% of the ammonium and aluminum had been removed. Kerr also showed that the true or normal hydrogen zeolite with... 

The ability of polyaminocarboxylic acids to form stable, water-soluble chelates over a wide pH range accounts for their diversity of uses. Ethylenediaminetetraacetic acid, H4EDTA, has played a central role in this development and stimulated interest in other complexones with a view to finding ligands with increased affinity and selectivity for metal ions. 

An example of a chelating ligand is ethylenediaminetetraacetic acid (H4EDTA) and its many relatives (Fig. 3.4). The six positions around Fe2+ are occupied by the two amine and four acetate groups. Chlorophyll and hemoglobin are also chelates. Chelates are quite soluble and tend to keep Fe, Zn, and Cu in solution for plant absorption. Chelates are also used to extract microelement and heavy metal ions from soils. The stability constant of theFe(III)-EDTA complex is... 

A number of chelates derived from ethylenediaminetetraacetic acid, H4EDTA, and diethylenetriaminepentaacetic acid, HjDTPA, have been examined... 

H4edta ethylenediaminetetraacetic acid tren 2,2, 2"-triami notriethylamine... 

This last proviso is exemplified as follows. Ethylenediaminetetraacetic acid should be rendered H4edta. The ions derived from it, which are often ligands in coordination entities, are then (H3edta) , (H2edta) , (Hedta) " and (edta) ". This avoids monstrosities such as edta-H2 and edtaH 2 which arise if the parent acid is represented as edta. A list of recommended abbreviations is presented in Table 4.5. 

H4edta ethylenediaminetetraacetic acid (ethane-1,2-diyldinitrilo)tetraacetic acid... 

H4edta, N,N -ethylenediaminetetraacetic acid H2edda, N,N -ethylenediaminediacetic acid H2mal, maleic acid H2ox, oxalic acid. 

Here the index "o/w" indicates the presence of L in both organic and aqueous phases. For example, for Zr +, U4+ and Pu4+ an ethylenediaminetetraacetic acid (EDTA, H4edta), which forms the neutral complexes [M(lV)edta]° might be a good choice, while for Am and Ln < EDTA is undesirable, but the dialkyl ester of diethylenetriaminepentaacetic acid (DTPA, Hsdtpa) - HsR2dtpa is expected to form the same zero charged species [Ln(R2dtpa)]°, where R indicated some alkyl. 

OxaUc acid is a diprotic acid denoted H20X. It is the ox anion that binds as a bidentate ligand. Ethylenediaminetetraacetic acid, a tetraprotic acid, is denoted H4EDTA. 

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