O=C(CN1CCN(c2ccccc2Cl)CC1)NC1CCCc2ccccc21.O=C(O)C(=O)O
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?