COC(=O)c1cc(NS(=O)(=O)c2cc(Br)cc3c2N(C(C)=O)CC3)cc(C(=O)OC)c1
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?