COc1cccc(-n2c(=O)c3sc4ccccc4c3n(CC(=O)Nc3ccccc3C)c2=O)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?