COc1ccc(-c2cc([N+](=O)[O-])ccc2OCC(=O)N(C)CC(=O)Nc2ccc(C)cc2)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?