COc1ccccc1NC(=O)N(CCCN1CCOCC1)Cc1cc2cc3c(cc2nc1O)OCO3
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?