O=C(NCc1ccc2c(c1)OCO2)c1nc(Cn2cc([N+](=O)[O-])cn2)no1
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?