Cc1ccc(Sc2ccc(N3CCCC(C(=O)Nc4ccc(Cl)cc4)C3)nn2)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?