O=C(Nc1ccnn1C1CCN(C(=O)c2c(F)cccc2F)CC1)C1CC1
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?