O=S(=O)(c1ccccc1)N1CCC(c2nc(O)c3nnn(Cc4c(F)cccc4Cl)c3n2)CC1
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?