COc1ccc(C(=O)Nc2cc(Cl)ccc2-n2cncn2)c(OC)c1OC
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?