O=C(C1=C(O)C(=O)N(CCCn2ccnc2)C1c1ccc(Br)cc1)c1ccc2c(c1)OCCO2
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?