O=C(O)c1cc(-c2ccc(-c3ccc(-c4cc(C(=O)O)c5cc(Cl)ccc5n4)cc3)cc2)nc2ccc(Cl)cc12
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?