Cc1ccc(NC(=S)N=Nc2c(O)n(C)c3ccc(S(=O)(=O)N4CCOCC4)cc23)cc1C
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?