O=C(NCc1ccco1)C(c1ccccc1)N(C(=O)Cc1cccs1)c1cccnc1
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?