O=C1C(/C=C/c2ccc(Cl)cc2)=NNC2N1N=C1NC(=O)C3(NN12)c1ccccc1-c1ccccc13
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?