C[C@@]1(C(NC(=O)c2cccs2)c2ccc(-c3ccccc3)cc2)C[C@H]1C1CCCCC1
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?