COc1ccc(N(C(=O)Nc2ccc(Cl)c(Cl)c2)C2c3cccn3C(=O)N2c2ccc(Cl)c(Cl)c2)cc1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?