O=C(/C=C/c1ccc([N+](=O)[O-])cc1)c1nc2ccccc2[nH]1
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?