O=C(NCCC[C@H]1CN2C(=NC[C@@H]2Cc2ccc(O)cc2)N1CCc1ccc(Cl)c(Cl)c1)C1CCC1
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?