O=C(NCC(=O)N1CCN(C(c2ccccc2)c2ccccc2)CC1)c1ccccc1F
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?