Oc1ccc(C[C@H]2CNC(=S)N2CC2CCCN2C[C@H](Cc2ccc(O)cc2)N2C[C@H](Cc3ccccc3)N(CC3CCCCC3)C2=S)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?