O=C(Cn1[nH]c(=O)c2ccccc2c1=O)OCC(=O)N(Cc1ccccc1)Cc1ccccc1
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?