COc1cc(/C=C(/C(=O)c2cccs2)c2nc3ccccc3[nH]2)cc(OC)c1O
The negative base-10 logarithmic of dissociation constant (pKa) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the negative pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the negative pKa value of this molecule?