O=C(N/N=C1/C[C@@H](O)[C@@H](O)[C@@H]2[C@@H]3C(=O)N(Cc4ccccc4)C(=O)[C@H]3CC[C@@H]12)OCc1ccccc1
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?