O=C(CSc1nnc(SCc2cccc3ccccc23)s1)N=Nc1c(O)[nH]c2ccccc12
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?