O=C(CSC1=Nc2ccccc2C2=NC(Cc3c[nH]c4ccccc34)C(=O)N12)NC1CCCCC1
The negative base-10 logarithmic of dissociation constant (pKa) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the negative pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the negative pKa value of this molecule?