COc1cccc(NC(=O)CC(=O)n2nc(-c3ccccc3)c(/N=N/c3ccc(Cl)cc3)c2-c2ccccc2)c1
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?