O/C(=C(\C([S-])=NCc1ccc2c(c1)OCO2)[n+]1ccccc1)c1ccc(Cl)s1
The negative base-10 logarithmic of dissociation constant (pKa) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the negative pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the negative pKa value of this molecule?