O=C1N[C@@H](Cc2ccccc2)C(=O)N2[C@H]1C[C@]1(Br)c3ccccc3N(S(=O)(=O)c3ccccc3)[C@H]21
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?