O=C(O)c1ccc(/C=C2\SC(=S)N(NC(=O)c3ccc(Br)cc3)C2=O)cc1
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?