O=[N+]([O-])c1ccc(NN=C(Nc2ccccc2)P(=O)(N2CCOCC2)N2CCOCC2)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?