Cc1ccc(CSc2ncc(Cl)c(C(=O)Nc3sc4c(c3C(N)=O)CCCC4)n2)cc1
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?