COc1cccc(Cn2c(=O)c(-c3cccs3)nc3cnc(Nc4ccccc4)nc32)c1
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?