COc1cccc(N2CCN(C3CC(=O)N(c4ccc(C)c(Cl)c4)C3=O)CC2)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?