Cc1ccccc1C(=O)Nc1cc[n+](-c2nc3ccccc3nc2[N-]S(=O)(=O)c2ccc(F)cc2)cc1
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?