O=C(Nc1ccc2c(c1)nc1n2CCN(C2CCCCC2)C1)c1ccco1
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 pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?