Nc1ccc(C(=O)N/C(=C\c2cccc([N+](=O)[O-])c2)c2nc3c4c(ccc3[nH]2)C(=O)c2ccccc2C4=O)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?