COc1ccccc1N1CCN(CCCN2C(C(=O)c3ccccc3)=C(O)c3c(C)cc(C)nc3S2(=O)=O)CC1
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?