COc1cc(CN2CCN(CCCSc3cc(C(C)(C)C)c(O)c(C(C)(C)C)c3)CC2)cc(OC)c1OC
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?