O=C(O)C(Cc1c[nH]c2ccccc12)NS(=O)(=O)c1ccc2ccccc2c1
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?