COc1ccc(C(OCC2OC(n3ccc(NC(=O)c4ccccc4)nc3=O)CC2OP2(=S)SCCS2)(c2ccccc2)c2ccc(OC)cc2)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?