COc1cc(OC)cc(C(=O)NC(=S)Nc2ccc(N3CCCC3)cc2)c1
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?