C[C@H](NC(=O)C1CCN(S(=O)(=O)c2ccccc2)CC1)C(=O)NCc1cccc(Cl)c1
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?