[N-]=[N+]=Nc1ccc2c(c1)Sc1ccccc1N2CCCCN1CCN(Cc2ccc(C(=O)c3ccc(CSCC(N)C(=O)O)cc3)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?