COc1ccc(CCN2C(=O)N(c3ccc(OC)cc3)C(=O)C2CC(=O)Nc2ccccc2)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?