NC(CCC(=O)O)C(=O)N1CCN(c2nc(N3CCCC3)c3nc(Cl)c(NCc4ccccc4)nc3n2)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?