Cc1ccc(C2c3c(C)nn(-c4ccc([N+](=O)[O-])cc4)c3N=C3C(=O)Nc4ccccc4N32)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?