O=S(=O)(c1ccccc1)[C@@H]1[C@H]2C=C[C@](CS)(O2)[C@H]1S(=O)(=O)c1ccccc1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?