O=C1NCN(c2ccccc2)C12CCN(C(c1ccnc3ccccc13)c1nnnn1-c1ccc3c(c1)OCCO3)CC2
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?