O=C(O)c1cc(-c2ccc(/C=C3/SC(=S)N(Cc4ccccc4)C3=O)o2)ccc1Cl
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?