O=C(NCCCn1ccnc1)c1cc2nc(-c3ccc(Br)cc3)cc(C(F)(F)F)n2n1
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?