COc1ccc(C[C@H]2CN3C(=NC[C@@H]3Cc3ccc(O)cc3)N2C[C@H](C)NC(=O)c2ccc(C)c(Br)c2)cc1
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?