COc1ccc(C(=O)Nc2cccc(/C(C)=N/NC(=O)c3ccc([N+](=O)[O-])c(C)c3)c2)cc1OC
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?