O=C1NC(=S)N(c2ccc(Cl)cc2)C(=O)/C1=C/Nc1ccc(N2CCOCC2)cc1
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?