COc1ccccc1CNC(=O)C1CCN(S(=O)(=O)c2ccc3nc4c(c(C(=O)O)c3c2)CCCC4)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?