O=C(NCc1ccccn1)c1ccc(CNS(=O)(=O)c2cccc(Cl)c2)cc1
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?