O=C1c2oc3ccccc3c(=O)c2C(c2cccc(Cl)c2)N1c1ccccn1
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?