O=C(CSc1nnnn1-c1cccc2ccccc12)NC(C(=O)O)(c1ccccc1)c1ccccc1
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?