Cn1c(=O)[nH]c(=O)c2c1nc(N1CCN(c3cccc(Cl)c3)CC1)n2CCCc1ccccc1
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?