Studies on the redox activity of iron N,O-complexes: Potential T₁-contrast agents

Figures & data

Scheme 1 Structures of the analyzed iron complexes. The geometries are based on X-ray structures of closely related complexes.

Figure 1 Percentage activity of iron complexes in the Haber–Weiss cycle.

Figure 2 Percentage activity of iron complexes in the Fenton reaction.

Figure 3 Result of sample degassing: FeSO₄·7H₂O (0.1 M), DMPO (5 M), and H₂O₂ (0.5 M).

Figure 4 Ascorbic acid oxidation with various Fe³⁺ compounds.

Table 1 Relative activity of iron complexes with selected ligands

Ligand	Fenton	Method, Ref.	Haber-Weiss	Method, Ref.	Ascorbate, Ref.
EDTA	100%		100%		100%
DFO	10%	C^Citation23	11%	C^Citation21	5%^Citation23
	7%	C^Citation12	1%	B^Citation24
			15%	C^Citation23
			13%	C^Citation12
DTPA	84%	A^Citation13	3%	A^Citation13
	670%	B^Citation24	<1%	B^Citation24
	50%	C^Citation12	33%	C^Citation12
	1%
Citrate	60%	A^Citation13	4%	A^Citation13
	58%	C^Citation12	14%	C^Citation12

Methods: A, xanthine oxidase followed by oxidation of formate to CO₂; B, pulse radiolysis followed by oxidation of formate to CO₂; C, hydroxylation of salicylate.

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