CC1=C(C(=O)Nc2ccccc2)C(c2ccco2)C(C#N)=C(SCc2ccccc2)N1
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?