O=C(O)C1CC=CCC1C(=O)N1CCN(c2nc(-c3ccccc3Cl)c3cc(Br)ccc3n2)CC1
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?