CCn1cc2nc(SCC(=O)Nc3ccc(OC)c(Cl)c3)n(Cc3ccc(OC)cc3)c(=O)c2n1
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?