COc1cc2cc(C(=O)N3CC(CCl)c4ccc([N+](C)(C)Cc5ccccc5[N+](=O)[O-])cc43)[nH]c2c(OC)c1OC.[Cl-]
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?