O=C(NCc1ccco1)C(c1ccccc1)N(Cc1ccccc1)C(=O)Cn1nnc2ccccc21
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?