O=C1c2[nH]nc(-c3ccccc3O)c2C(c2cccc(OCc3ccccc3)c2)N1CCO
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?