Encouraged by these findings, we prepared films made incorporating
the two derivatives (SP1 and SP2) and studied their H+ binding behaviour.
A small piece of the film was cut, exposed to UV light for 1 min thereby trnasforming SP1 and SP2 into MC1 and MC2, respectively, and then immersed in universal buffer of known pH.
The results are shown in Fig. 5.
The line drawn through the experimental data points (marked
as circles) was obtained by treating the equilibrium between the
ligands and H+ ion (nL+mMn+→MmLn where L denotes ligand and
M stands for ion of interest of charge n).