engleski

Estimation of stability constants of copper(II) and nickel(II) chelates with dipeptides by using topological indices

The estimation of the overall stability constants β 1 of copper(II) and nickel(II) chelates with dipeptides by using the model with the valence connectivity index of the 3rd order (3χ v) was performed by dividing β 1 to their constituting constants K1 and Ka, and subsequently by dividing the basic set into subsets or treating the chelate rings as separate units. Altogether 15 copper(II) and eight nickel(II) chelates with dipeptides were investigated. Six models for the estimation of log K1 and pKa were checked, most of them by usage of indicator variables (for differentiation of copper(II) and nickel(II) complexes or subclasses of ligands). Estimates of log β 1 gave the range of S.E.cv values from 0.19 to 0.27. For the best model errors of estimates were less than 0.34.

Connectiviy index; Linear regression models; Indicator variable; Hydrophobicity parameters

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