O=C1[C@H]2C(c3ccc(Cl)cc3)N(c3ccccc3)O[C@H]2C(=O)N1c1ccc(Cc2ccc(N3C(=O)[C@H]4ON(c5ccccc5)C(c5ccc(Cl)cc5)[C@H]4C3=O)cc2)cc1
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 pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?