O=C(NC(=S)Nc1ccccc1C(=O)O)c1ccc(-c2ccc(Br)cc2)o1
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?