Modeling of stability constants of mono-complexes of La3+, Ce3+, Pr3+, and Nd3+ with carboxylic acids in water–dioxane solutions by using connectivity index 3χv

We developed two models for the estimation of stability constants in dioxane–water mixtures of mono-complexes of lanthanides (La3+, Ce3+, Pr3+, and Nd3+) with carboxylic acids (ethanoic, propanoic, and butanoic). The first, linear model proved suitable for the prediction of log K1 at low mass fractions of dioxane, w = 0–20% (r = 0.981, S.E. = 0.06), whereas the second, quadratic model, yielded better results at higher fractions, w = 40–60% (r = 0.980, S.E. = 0.10).