Table 2

Electrochemical and stability constant data for Fe(III) complexes with selected "model" ligands47and natural siderophores.[48] Measurements were made in 5 mM Bistris buffer adjusted to 0.1 M ionic strength with NaCl
Complexa
 pH
 E'p b/V vs. SCE
 Log Ki c (I = 0.1, 25°C)
Model ligands


1. [FeCDTA]-
 7
 -0.145
 30.0
2. [FeNTAtiron]--
 7
 -0.182
 31.7
3. [FeNTAcat]2-
 7
 -0.211
 32.9
4. [Fe(cat)2]-
 7
 -0.354
 34.7
5. [Fe(4Ncat)3]3-
 7
 -0.440
 40.0
6. [Fe(cat)3]3-
 10
 -0.680
 43.7
7. [Feent]3-
 7
 -0.924
 49.0




Siderophores


8. [Fe(Alt-B)2]
 6
 -0.428
 37.6
9. [Fe(Alt-B)2]
 8.2
 -0.672
 43.6
10. Fe-PCC7002 No. 1
 7
 -0.445
 38.1
11. Fe-PCC7002 No. 3
 7
 -0.618
 42.3
12. Decapeptides mefpl
 7
 ~-0.510
 39.6
13. mefpl
 7
 -0.542
 41.6

aCDTA = cis-l,2-cyclohexylenedinitrilotetraacetate, NTA = nitrilo-triacetate, tiron = 4,5-dihydoxy-l,3-benzene disulfonic acid, cat = catechol, 4Ncat = 4-nitrocatechol, ent = enterobactin, Alt-B = altero-bactin B, PCC7002 = Synechococcus sp. PCC7002 isolates (complex stoichiometry is not known for eqn.(10) and (11)). b ± 10 mV. cSee Table 1 of ref. 47 for references.

Luther et al. Geochemical Transactions 2001 2:65   doi:10.1186/1467-4866-2-65