Cc1ccc(Cl)cc1Nc1nc(-c2sc(NC(=O)c3cccc(Cl)c3)nc2C)cs1
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?