Complex formation with heptane-3,5-dione. Stabilities of some bivalent metal chelate complexes in aqueous dioxan (50%)

Abstract

The acid dissociation constant of heptane-3,5-dione together with the stability constants of its chelate complex with cobalt(II), have been determined in aqueous dioxan (50% v/v) over the temperature range 5–45 °C. From these results, values of the enthalpy and entropy of protonation and chelation have been calculated. Stability constants of heptane-3,5-dione chelate complexes of copper(II), nickel(II), manganese(II) and magnesium(II) have been measured at 25 °C.