O=C(CC1N=C2c3ccccc3N=C(SCC(=O)Nc3ccccc3F)N2C1=O)NCc1cccs1
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?