COc1ccccc1C1NC(c2ccc3c(c2)OCO3)=CC(c2ccccc2O)N1
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?