Cc1cccc2nc(CSc3nc4cc([N+](=O)[O-])ccc4[nH]3)c(Br)n12
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?