N#CC1=C([C-](C#N)C#N)NC(O)(c2ccccc2)C([n+]2ccccc2)C1c1cccs1
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?