Nc1ncnc2c1ncn2[C@@H]1O[C@H](CNCc2cccc(C#Cc3ccccc3)c2)[C@@H](O)[C@H]1O
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?