O=C(NCCC(=O)N(CCc1ccccc1)Cc1ccccc1)c1ccc([N+](=O)[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?