O=C(NCC(=O)N(c1ccc(F)cc1)C(C(=O)NC1CCCC1)c1cccnc1)c1cccs1
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?