O=C(COC(=O)C1CC(=O)N(Cc2ccco2)C1)Nc1ccccc1[N+](=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?