Cc1n[nH]c2c1C(c1c(C)nn(-c3ccccc3)c1Cl)C(C#N)=C(N)O2
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?