O=C1[C@H]2C(c3ccccc3[N+](=O)[O-])=[N+](c3ccccc3)O[C@H]2C(=O)N1c1ccc(Cc2ccc(N3C(=O)[C@H]4O[N+](c5ccccc5)=C(c5ccccc5[N+](=O)[O-])[C@H]4C3=O)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?