O=C(Nc1cccc(S(=O)(=O)NC2=NCCC2)c1)c1cc(-c2ccccn2)nc2ccccc12
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?