O=C(NC1CCN(Cc2ccccc2)CC1)c1ccc(Cn2c(=S)[nH]c3ccc(N4CCOCC4)cc3c2=O)cc1
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?