O=C(Nc1cc([N+](=O)[O-])c2nc(O)c3ccccc3c2c1)C(F)(F)F
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?