Figure 2. Plot of the relation between p-phenols toxicity, log(1/IC 50), and QTAIM charges of Cu atoms of data sets A (black squares), B (red circles) and C (blue triangles). Dashed lines correspond to linear parameters in Table 2.
Copper charges in the2[Ph Cu]2+complexes (as compared with original2Cu2+ ion charges) are a measure of the O → Cu electron density transfer (Table S1 in Supplementary information) and reflect the phenol toxicity (Table 2, Figs. 2, S2 and S3 in Supplementary information). The QTAIM charges exhibit better statistical parameters for Eq. (2) than the NBO and MPA ones, especially for the dataset A (Table 2). Nevertheless, in all cases their fit is better than for the Cu-O distances above.