CCOc1ccc(Cn2c(CNS(=O)(=O)c3ccc([N+](=O)[O-])cc3)nc3cccnc32)cc1
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?