O=C(Nc1c(O)[nH]c(=S)[nH]c1=O)c1ccc2ccccc2n1
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?