N#CCSC1=Nc2ccccc2C2=NC(CCC(=O)N3CCN(c4ccccc4)CC3)C(=O)N12
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?