COc1ccc(C(=O)N2CCN(c3cccc(Cl)c3)CC2)cc1S(=O)(=O)NC1CC1
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?