O=C(NNC(=O)C1CCCN(S(=O)(=O)c2ccc3ccccc3c2)C1)C1CC1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?