O=C(CSc1nc2c(sc3ccccc32)c(=O)n1CCc1ccccc1)NCc1ccco1
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?