Microequilibrium treatment that has previously been limited to tridentate ligands is generalized to arbitrary number of functional groups in the molecule and the role of symmetry is also investigated. Cumulative microconstant, a new type of equilibrium parameter, is introduced, allowing an equivalent, but more compact mathematical treatment of large microequilibrium systems. The sufficient number of independent pieces of information for the unambiguous determination of all microconstants is deduced. It has been concluded that even if protonation mole fraction for all the basic sites is available, determinability of all the microconstants is rather the exception than the case, without a priori simplifying assumptions. It has been shown that all microconstants can only be determined from protonation mole fractions for molecules of up to three groups. For molecules of four groups and beyond, only specific symmetry and the concomitant simplification of the microequilibrium system make the strict, complete microspeciation feasible. As a case study, the protonation scheme and the complete microspeciation of a tetradentate ligand is analyzed in detail.
ASJC Scopus subject areas
- Applied Mathematics