CCn1c(SCC(=O)Nc2cc(Cl)ccc2OC)nc2c([nH]c3ccccc32)c1=O
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?