COc1cc(CN2CCCC(C(=O)c3ccc(C(C)(C)C)cc3)C2)cc(OC)c1O
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?