Table 1.

Purchased benzamides for core structure analysis. All the compounds were inactive and pyridylbenzamides 7–10 formed a pink precipitate upon monodentate coordination to the Fe center at the indicated concentration range when added to a solution of 100 μM Fe(III)PPIX and 30.5 μM NP40 at pH 4.8.

Code	Concentration range at which precipitate forms (μM)
1 – 6	N/A (Inactive ≤ 5500 μM)
7	4500–5500
8	1300–2300
9	700–1300
10	1300–2300

1: R₁ = H; X = N

2: R₁ = 4-NO₂; X = CH

3: R₁ = 4-NO₂; X = N

4: R₁ = 2,4-di-NO₂; X = N

5: R₁ = 4-CH₃; X = N

6: R₁ = 4-OCH₃; X = N

7: R₁ = 4-Cl; X = N

8: R₁ = 3-Cl; X = N

9: R₁ = 3,4-di-Cl; X = N

10: R₁ = 3-CF₃; X = N