COc1c(Cl)cc(C(=O)Nc2cc(-c3nc4ccccc4[nH]3)ccc2C)cc1Cl
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?