C[C@@H](NC(=O)c1cc2c([nH]c3ccccc32)c(-c2ccccc2)n1)C(=O)O
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?