EDDS

EDDS

Names
IUPAC name Ethylenediamine-N,N′-disuccinic acid
Identifiers
CAS Number	20846-91-7 Y
3D model (JSmol)	Interactive image Interactive image
ChemSpider	109992 N 9489961 2-[(2-{[(1S)-1-Carboxyethyl]amino}ethyl)amino] N 8283888 (2R)-2-[(2-{[(1R)-1-Carboxyethyl]amino}ethyl)amino] N 435376 (2S)-2-[(2-{[(1S)-1-Carboxyethyl]amino}ethyl)amino] N
MeSH	N,N'-ethylenediamine+disuccinic+acid
PubChem CID	123395 11314994 2-[(2-{[(1S)-1-Carboxyethyl]amino}ethyl)amino] 10108362 (2R)-2-[(2-{[(1R)-1-Carboxyethyl]amino}ethyl)amino] 497266 (2S)-2-[(2-{[(1S)-1-Carboxyethyl]amino}ethyl)amino] 46218600 (2S)-2-[(2-{[(1R)-1-Carboxyethyl]amino}ethyl)amino]
InChI InChI=1S/C10H16N2O8/c13-7(14)3-5(9(17)18)11-1-2-12-6(10(19)20)4-8(15)16/h5-6,11-12H,1-4H2,(H,13,14)(H,15,16)(H,17,18)(H,19,20) N Key: VKZRWSNIWNFCIQ-UHFFFAOYSA-N N
SMILES [o]:c(:[oH])CC(NCCNC(Cc(:[o]):[oH])c(:[o]):[oH])c(:[o]):[oH] OC(=O)CC(NCCNC(CC(O)=O)C(O)=O)C(O)=O
Properties
Chemical formula	C10H16N2O8
Molar mass	292.24 g·mol−1
Density	1.44 g mL−1
Melting point	220 to 222 °C (428 to 432 °F; 493 to 495 K)
Acidity (pKa)	2.4
Basicity (pKb)	11.6
Thermochemistry
Std enthalpy of formation (ΔfHo298)	−1.9541–−1.9463 MJ mol−1
Std enthalpy of combustion (ΔcHo298)	−4.2755–−4.2677 MJ mol−1
Related compounds
Related alkanoic acids	EDTA
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Ethylenediamine-N,N'-disuccinic acid (EDDS) is an aminopolycarboxylic acid. It is a colourless solid that is used as chelating agent that may offer a biodegradable alternative to EDTA, which is currently used on a large scale in numerous applications.

EDDS has two chiral centers, and as such three stereoisomers. These are the enantiomeric (R,R) and (S,S) isomers and the achiral meso (R,S) isomer. As a biodegradable replacement for EDTA, only the (S,S) stereoisomer is of interest. The (R,S) and (R,R) stereoisomers are less biodegradable, whereas the (S,S) stereoisomer has been shown to be very effectively biodegraded even in highly polluted soils.

EDDS was first synthesized from maleic acid and ethylenediamine. Some microorganisms have been manipulated for industrial-scale synthesis of (S,S)-EDDS from ethylenediamine and fumaric acid or maleic acid, which proceeds as follows:

(S,S)-EDDS is produced stereospecifically by the alkylation of an ethylenedibromide with L-aspartic acid. Racemic EDDS is produced by the reaction of ethylenediamine with fumaric acid or maleic acid.

In comparing the effectiveness of (S,S)-EDDS versus EDTA as chelating agents for iron(III):

Because of the lower stability for [Fe(S,S)-EDDS]⁻, the useful range being roughly 3<pH_(S,S)-EDDS<9 and 2<pH_EDTA<11. However, this range is sufficient for most applications.

Another comparison that can be made between (S,S)-EDDS and EDTA is the structure of the chelated complex. EDTA’s six donor sites form five five-membered chelate rings around the metal ion, four NC₂OFe rings and one C₂N₂Fe ring. The C₂N₂Fe ring and two of NC₂OFe rings define a plane, and two NC₂OFe rings are perpendicular to the plane that contains the C₂-symmetry axis. The five-membered rings are slightly strained. EDDS’s six donor sites form both five- and six-membered chelate rings around the metal ion: two NC₂OFe rings, two NC₃OFe rings, and one C₂N₂Fe ring. Studies of the crystal structure of the Fe[(S,S)-EDDS]⁻ complex show that the two five-membered NC₃OFe rings project out of the plane of the complex, reducing the equatorial ring strain that exists in the Fe[EDTA]⁻ complex. The complex also has C₂ symmetry.