COc1ccc(C)cc1Nc1n[n+](C)c(-c2c3ccccc3cc3ccccc23)s1.[Cl-]
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?