COc1cc(O)c(C(CCN2CCCC(C)C2)c2cc(OC)c(OC)c(OC)c2)c(OC)c1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?