O=C(O)c1ccc(/C=C2\SC(=S)N(Nc3ccccc3)C2=O)cc1
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?