Cn1c(SCC(=O)Nc2cccc(C(=O)O)c2)nnc1-c1cc2cc(Br)ccc2o1
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?