O=C(O)c1cc(NC(=O)c2cccc(N3C(=O)c4ccccc4C3=O)c2)cc(C(=O)O)c1
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?