COc1ccc(-n2c(SCC(=O)N(C)c3ccccc3)nc3c4ccccc4nc-3c2O)cc1OC
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?