O=C(CCN1C(=O)/C(=C/C=C/c2ccccc2)SC1=S)Nc1cccnc1
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?