O=C(CCn1c(=O)[nH]c2ccccc2c1=O)NCCCN1CCN(c2cccc(Cl)c2)CC1
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?