Alternatively, the charge and spin population of Cu was evaluated in
terms of Quantum Theory of Atoms-in-Molecules
(QTAIM)[17] (see Supplementary Information for
details). The O → Cu electron density transfer was alternatively
estimated as the Laplacian of the electron density
(∇2ρ) at Cu – O bond critical points (BCP) using
AIMAll software.[18] The MOLDRAW
software[19] was used for geometry manipulation
and visualisation purposes.
MIA is evaluated as the interaction energy
Eint = Ecomplex –ECu(II) - EPh (1)
where E complex is the DFT energy of the2[Ph… Cu]2+complex, E Cu(II) is the DFT energy of the
Cu2+ ion and E Ph is the DFT
energy of the p-substituted phenol molecule.
The standard linear regression analysis was used to obtain the
regression parameters a and b of the relation
log (1/IC 50) = a X + b (2)
where log(1/IC 50) are the experimental
toxicity data of Selassie et al .[2] and X
stands for predictor variables under study. The goodness of fit is
evaluated by standard statistical parameters such as the coefficient of
determination R2 or the critical value α of the
F-test.