O=C(C1=C[C@@H]2[C@H]3C(=O)N(c4ccccc4Cl)C(=O)[C@H]3[C@@H](C(=O)c3ccc(Cl)cc3)N2C=C1)c1ccccc1
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?