COc1ccc(S(=O)(=O)Cc2ccc(C(=O)NCCCN3CCc4ccccc4C3)o2)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?