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. 2024 Nov 4;4(6):292–306. doi: 10.1021/acsenvironau.4c00037

Table 2. Stability Constants Experimentally Determined for Complexes of Trivalent Actinium, Americium, and Curium with Small Biorelevant Chelators (DFOB = Desferrioxamine B. PYOV = Pyoverdine. SHA = Salicylhydroxamate. BHA = benzohydroxamate).

chelator reaction formation constant conditions ref
carbonate Am3+ + CO32– = [AmCO3]+ log β11 = 5.97 I = 0.1–0.3 M (NaClO4), T = 25 °C (55)
Am3+ + 2 CO32– = [Am(CO3)2] log β12 = 9.58
[Am2(CO3)3](s) = 2 Am3+ + 3 CO32– log Ksp = −29.70
[Cm(CO3)2] + CO32– = [Cm(CO3)3]2– log K3 = 2.01 I = 3 M (NaClO4), T = 25 °C (57)
phosphate Ac3+ + H2PO4 = [AcH2PO4]2+ log K = 1.85 I = 0, T = 30 °C (78)
Am3+ + H2PO4 = [AmH2PO4]2+ log K = 2.13 I = 0, T = 30 °C (79)
Am3+ + HPO42– = [AmHPO4]+ log K = 4.14
Cm3+ + 2 H+ + PO43– = [CmH2PO4]2+ log β121 = 22.02 I = 0.1 M (NaClO4), T = 24 °C (80)
Cm3+ + H+ + PO43– = [CmHPO4]+ log β111 = 18.56
Cm3+ + H3PO4 = [CmH2PO4]2+ + H+ log K = −0.14 I = 1.1 M (NaClO4), T = 25 °C (81)
oxalate Ac3+ + C2O42– = [AcC2O4]+ log β11 = 3.56 I = 1 M (NaClO4), T = 25 °C (82)
Ac3+ + 2 C2O42– = [Ac(C2O4)2] log β12 = 6.16
Am3+ + C2O42– = [AmC2O4]+ log β11 = 4.63 I = 1 M (NaClO4), T = 25 °C (82)
Am3+ + 2 C2O42– = [Am(C2O4)2] log β12 = 8.35
Am3+ + 3 C2O42– = [Am(C2O4)3]3– log β13 = 11.15
Am3+ + C2O42– = [AmC2O4]+ log β11 = 5.34 I = 0.1 M (NaClO4), T = 23–26 °C (62)
Am3+ + 2 C2O42– = [Am(C2O4)2] log β12 = 9.14
Am3+ + 3 C2O42– = [Am(C2O4)3]3– log β13 = 11.49
acetate Cm3+ + Acetate = [CmAcetate]2+ log β11 = 3.18 I = 0, T = 20 °C (83)
Cm3+ + 2 Acetate = [Cm(Acetate)2]+ log β12 = 4.80
Cm3+ + 3 Acetate = [Cm(Acetate)3] log β13 = 5.19
malonate Cm3+ + Malonate2– = [CmMalonate]+ log β11 = 5.26 I = 0, T = 20 °C (84)
Cm3+ + 2 Malonate2– = [Cm(Malonate)2] log β12 = 8.38
propionate Cm3+ + Propionate2– = [CmPropionate]2+ log β11 = 3.24 I = 0, T = 25 °C (85)
Cm3+ + 2 Propionate2– = [Cm(Propionate)2]+ log β12 = 4.63
citrate Cm3+ + HCitrate3– = [CmHCitrate] log K1 = 7.4 I = 0.1 M (NaClO4), T = 23–25 °C (46)
Cm3+ + 2 HCitrate3– = [Cm(HCitrate)2]3– log K2 = 11.3
Cm3+ + H2Citrate2– + HCitrate3–= [Cm(H2Citrate)HCitrate]2– log K = 11.0
desferrioxamine B (DFOB) Cm3+ + DFOB3– = [CmDFOB] log β101 = 16.80 I = 0.1 M (NaClO4), T = 25 °C (73)
Cm3+ + DFOB3– + H+ = [CmHDFOB]+ log β111 = 25.73
Cm3+ + DFOB3– + 2 H+ = [CmH2DFOB]2+ log β121 = 31.62
Am3+ + DFOB3– + H+ = [AmHDFOB)]+ log β111 = 25.5 I = 1 M (KNO3), T = 25 °C (86)
Am3+ + DFOB3– + 2 H+ = [AmH2DFOB]2+ log β121 = 32.2
Am3+ + DFOB3– + 3 H+ = [AmH3DFOB]3+ log β131 = 37.9
Am3+ + 2 DFOB3– + 4 H+ = [AmH4(DFOB)2]4+ log β142 = 60.5
pyoverdin (PYOV) Cm3+ + PYOV4– = [CmPYOV] log β 101 = 19.30 I = 0.1 M (NaClO4), T = 25 °C (74)
Cm3+ + HPYOV3– + H+ = [CmHPYOV] log β 111 = 27.40
Cm3+ + PYOV2– + 2 H+ = [CmH2PYOV]+ log β 121 = 32.50
salicylhydroxamate (SHA) Cm3+ + SHA2+ + H+= [CmSHA]2+ log β 111 = 16.52 I = 0.1 M (NaClO4), T = 25 °C (75)
Cm3+ + 2 SHA + H+ = [CmH(SHA)2] log β 112 = 24.09
benzohydroxamate (BHA) Cm3+ + BHA2+ = [CmBHA]2+ log β 111 = 6.52 I = 0.1 M (NaClO4), T = 25 °C (75)
Cm3+ + 2 BHA = [CmH(BHA)2] log β 112 = 11.60
humic acid (HA) Am3+ + HAx = [AmHA]x−3 log β 11 = 6.27 I = 0.1 M (NaClO4), pH 6. Note: Two different sources of humic acids (Aldrich and Bradford – see original reference) (70)
log β 11 = 6.36