O=C(NCc1ccc(Cl)cc1)c1ccc2c(=O)n(CC3CCCO3)c(=S)[nH]c2c1
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?