COc1ccc(CCN2C(S)=NC3CC2(C)Oc2ccc([N+](=O)[O-])cc23)cc1OC
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?