COC(=O)C(Cc1nc2ccc(Cl)cc2nc1O)/C(=N\N)C(=O)Nc1cc(C)c(Cl)cc1S(=O)(=O)O
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?