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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

From: Metal–organic complexation in the marine environment

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
  1. 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.