O=C(OCC(=O)c1ccc(S(=O)(=O)N2CCCC2)cc1)C1=COCCO1
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?