Cc1ccc(OCC(=O)OCc2nc(O)c3c(-c4ccccc4)csc3n2)cc1C
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?