The examined ligands are characterized, with the exception of L7
alone, by the presence of two kojic units joined by different linkers.
They all form with Cu2+ dinuclear complexes with different degrees
of protonation, and L1, L4 and L5 form also 1:1 complexes. Only L7 ligand
forms mononuclear 1:1 and 1:2 complexes. In the case of Zn2+,
mononuclear 1:1 and binuclear 2:2 complexes, are formed