O=C(Nc1ccccc1)C1=C[C@H](c2ccc(Br)cc2)C[C@H](OCc2ccc(CO)cc2)O1
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?