COc1ccc(C(=O)Nc2nc(-c3ccc([N+](=O)[O-])cc3)c(-c3ccc(OC)cc3)s2)cc1
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?