COc1cc(CCC(=O)Nc2c(C(=O)N3CCN(c4ccccc4)CC3)oc3ccccc23)on1
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?