Cc1ccccc1N/C(SCc1ccc(Cl)cc1)=C(/C#N)C(=O)NCc1ccco1
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?