The speciation of metal-ligand complexes is driven by the stochiometric quantities of the metal ions and ligands in the reaction media. This is illustrated by a speciation analysis of Ni and histamine (see Methods), which has also been demonstrated in recent work (Fig. ). This example analysis shows that the dominant coordination number of the metal-ligand complexes in the reaction media is strongly stoichiometry-dependent, such that the metal-ligand ratio can be adjusted to preferentially form mono, bis, or tris coordination complexes. The manipulation of the coordination number via the reaction media stoichiometry will in turn significantly affect the structure and stability of the complexes, which we aim to characterize in this work.