O=C(NC(CO)Cc1ccc(Oc2cc(CC(CO)NC(=O)OCc3ccccc3)ccc2OC(=O)OCc2ccccc2)cc1)OCc1ccccc1
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?