O=C1CSC2(CC(/C=C/c3ccccc3Br)=NN2c2cccc(S(=O)(=O)O)c2)N1c1nc2ccccc2s1
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?