CC(C)CCn1c(N2CCN(c3cccc(Cl)c3)CC2)nc2c1c(=O)[nH]c(=O)n2C
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?