O=C(O)c1ccc(CSc2nc3n(n2)C(c2cccs2)C2=C(O)CCCC2=N3)cc1
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 pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?