O=C1[C@@H]2[C@@H]3CCCN3[C@@]3(C(=O)Nc4ccccc43)[C@@H]2C(=O)N1c1cc(Cl)cc(Cl)c1
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?