COc1cc(C(c2c(C)n[nH]c2O)c2c(C)n[nH]c2O)ccc1OS(=O)(=O)c1ccc(C)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?