. 2019 Mar 12;48(13):4299–4313. doi: 10.1039/c8dt04454f

Table 2. Acid dissociation and conditional Fe³⁺ and Ga³⁺ complex formation constants for THP^Me and THP^H. Estimated overall error for each value <3%. pM values were calculated based on [M]_total = 1 μM, [L]_total = 10 μM and pH = 7.4.

	THP^Me	THP^H	Deferiprone ^a
pK_a1	3.2 ^b	3.4 ^b	3.5
pK_a2	9.4 ^b	9.5 ^b	9.8
pK_a3	N/A	13.0 ^c	N/A
pFe	29.1	28.6	20.8
pGa	30.0	31.8	20.7

^aPreviously reported measurements on deferiprone33 were repeated here to confirm the reliability of our titration method.

^bIntrinsic pK_a values45 were determined from spectrophotometric titration. When deviation from the obtained intrinsic pK_a values were considered (±0.2–0.8 log units), no significant changes in pM values (less than 3%) were observed.

^cEstimated pK_a value. No significant spectral change was observed between pH 11.5 and 12.5 for pK_a titration. Changing the estimated pK_a value can result in different metal log β values for THP^H but no appreciable change in pM values.

Table 2. Acid dissociation and conditional Fe3+ and Ga3+ complex formation constants for THPMe and THPH. Estimated overall error for each value <3%. pM values were calculated based on [M]total = 1 μM, [L]total = 10 μM and pH = 7.4.

Table 2. Acid dissociation and conditional Fe³⁺ and Ga³⁺ complex formation constants for THP^Me and THP^H. Estimated overall error for each value <3%. pM values were calculated based on [M]_total = 1 μM, [L]_total = 10 μM and pH = 7.4.