CCCn1c(N)c(C(=O)CSc2nnc(-c3ccco3)n2Cc2ccccc2)c(=O)[nH]c1=O
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?