O=S(=O)(N/N=C/c1ccc(/C=N/NS(=O)(=O)c2ccccc2)cc1)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?