CCC(=O)Nc1cc[n+](C2=Nc3ccccc3[N-]C2=C(C#N)C#N)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?