Complexation of Mn ²⁺, Fe ²⁺, Y ³⁺, La ³⁺, Pb ²⁺, and UO 2²⁺ with organic ligands: QSPR ensemble modeling of stability constants

Quantitative structure–property relationship (QSPR) modeling of the stability constant logK of the 1:1 (M:L) complexes of 6 transition-metal cations (M) with 261 (Mn2+), 87 (Fe2+), 105 (Y3+), 186 (La3+), 226 (Pb2+), and 66 (UO22+) organic ligands (L) in aqueous solutions at 298 K and an ionic strength 0.1 M was performed using ensemble multiple linear regression analysis and substructural molecular fragments as descriptors. The models have been validated in external 5-fold cross-validations procedure and on new ligands recently reported in the literature. Predicted logK values were calculated by consensus models as arithmetic means of 315 (Mn2+), 119 (Fe2+), 260 (Y3+), 290 (La3+), 304 (Pb2+), and 249 (UO22+) individual models. Absolute prediction error of logK is below 1.0 for 75% (UO22+), 70% (Mn2+, Fe2+, La3+), 65% (Pb2+), and 60% (Y3+) of the ligands and comparable with the systematic errors in experimental data. The developed QSPR models were used to screen selective ligands for the studied cations. T...