COc1ccc(CNc2nc(NCc3ccc(OC)c(OC)c3)n(C(=O)c3cccs3)n2)cc1OC
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?