COc1ccc2c(c1)c1c(c(=O)n(Cc3ccccc3)c(=O)n1CC(=O)Nc1c(C)cccc1C)n2C
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?