COc1ccc2nc3cc([N+](=O)[O-])ccc3c(Nc3ccc(S(=O)(=O)NC(C)=O)cc3)c2c1
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?