Cc1ccc2nc(NC(=O)C3CCN(S(=O)(=O)c4cc([N+](=O)[O-])ccc4Cl)CC3)sc2c1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?