Supramolecular analytical chemistry has emerged as a new discipline at the interface of supramolecular and analytical chemistry. It focuses on analytical applications of molecular recognition and self-assembly. One of the important outcomes of the supramolecular analytical chemistry is the understanding of molecular aspects of sensor design, synthesis and binding studies of sensors while using rigorous methods of analytical chemistry as a touchstone to verify the viability of the supramolecular aspects of the sensor design. This critical review provides a simplified version of the chemometric procedures involved in realizing a successful analytical experiment that utilizes cross-reactive optical sensor arrays, and summarizes the current research in this field. This review also shows several examples of use of described chemometric methods for evaluation of chemosensors and sensor arrays. Thus, this review is aimed mostly at the readers who want to test their newly-developed chemosensors in cross-reactive arrays (169 references).

New bifunctional H₄dota-like ligands with three acetic acid and one phosphinic acid pendant arms and propionate (H₅do3ap^PrA) or 4-aminobenzyl (H₄do3ap^ABn) reactive groups bound to the phosphorus atom were investigated. Potentiometric studies showed that the ligands have a similar basicity to the parent H₄dota and the stability constants of their complexes with sodium(I) and selected lanthanide(III) ions are also similar. Formation and acid-assisted decomplexation kinetics of yttrium(III) complexes with a series of H₄dota-like ligands (H₄dota and its phosphinic/phosphonic acid analogues) were studied and the reactions are sensitive to a slight modification of the ligand structure. The (2-carboxyethyl)phosphinic acid derivative H₅do3ap^PrA and the phosphonic acid ligand H₅do3ap form complexes faster than H₄dota. The most kinetically inert complex is that with H₄do3ap^ABn. Rates of complexation and decomplexation can depend on the ability to transfer proton(s) outside/inside the complex cavity and, therefore, on the hydrophobicity of the ligands. The results demonstrate that the new bifunctional ligands are suitable for labelling biomolecules with yttrium(III) radioisotopes for utilization in nuclear medicine.

Solution properties of complexes of a new H₄dota-like ligand containing three acetate and one methylphosphonate pendant arms (H₅do3ap, H₅L) were studied. The ligand exhibits a high last dissociation constant (pK_A = 13.83) as a consequence of the presence of phosphonate moiety. In solution, successive attachment of protons leads to several reorganizations of protonation sites and the neutral zwitterionic species H₅do3ap has the same solution structure as in the solid state, where the nitrogen atom binding methylphosphonate and the opposite nitrogen atoms are protonated. Stability constants with Na⁺ and trivalent lanthanide ions (La³⁺, Ce³⁺, Eu³⁺, Gd³⁺, Lu³⁺) and Y³⁺ have been determined. The constants are comparable or higher than those of H₄dota due to the higher overall basicity of H₅do3ap. Formation of the stable protonated complexes, as well as complexes with the L:M = 1:2 stoichiometry, was proved. Formation and decomplexation kinetics of the Ce³⁺ and Gd³⁺ complexes were investigated. The mechanism of formation of the H₅do3ap complexes is similar to that observed for H₄dota complexes and the complex species with mono- or diprotonated ligand on the cyclen ring are considered as the reaction intermediates. Acid-assisted decomplexation of H₅do3ap complexes is faster in comparison with those of H₄dota. This is caused by higher basicity of the phosphonate pendant arm and the ring nitrogen atoms, which facilitates the proton transfer from the bulk solution to the nitrogen atoms of cyclen ring.