Estimation of stability constants of coordination compounds using models based on topological indices

The principal aim of our research was to develop theoretical models for estimating stability constants of coordination compounds, focusing on chelates of heavy metals, Cu(II) and Ni(II), with bioligands (amines, amino acids and peptides). We tried to solve the problem using graph-theoretical models. We also encountered a specifi c problem for coordination compounds – the choice of the constitutional formula, that is graph, of the complex species. KEY WORDS: copper(II) chelates, nickel(II) chelates, valence connectivity index There are two kinds of models in chemistry. The fi rst treat molecule as a system of electrons and nuclei, and solve problems in a typical physical way, by solving equations of motion of these particles. This kind of modelling includes quantum-chemical method, and conceptually similar models that stem from statistical mechanics. The second kind is based on the chemical way of thinking, namely on the comparison of relate