Fc1cc(C2=C[C@H](c3ccc(Cl)cc3)NC(=S)N2)c(Cl)cc1Cl
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?