Cc1cccc(N=C(S)N(CCCN(C)C)Cc2cc3cc4c(cc3nc2O)OCO4)c1
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?