O=C(COC(=O)c1cccc2c(=O)c3ccccc3[nH]c12)Nc1ccc(S(=O)(=O)Nc2ncccn2)cc1
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?