C[C@H](NC(=O)c1[nH]cnc1C(=O)NCc1ccccc1)C(=O)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?