O=C(O)C12C[C@@H]3C[C@H](C1)CC(n1ncc(N4CCN(c5ccccc5)CC4)c(Cl)c1=O)(C3)C2
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?