Cc1n[nH]c(S/C(=C\c2ccc(-c3ccc(C(=O)O)c(Cl)c3)o2)C(=O)O)n1
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?