O=C1OCCN1C(=O)[C@H]1[C@H](c2ccc([N+](=O)[O-])cc2)C(c2ccc(F)cc2)=NN1c1ccccc1
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?