O=C(Nc1cccc(C(=O)O)c1)/C(=C\c1ccc2c(c1)OCO2)NC(=O)c1ccc(Br)cc1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?