Br.COc1cccc(Nc2nc(-c3cccc(N4C(=O)c5ccccc5C4=O)c3)cs2)c1
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?