O=C(CC(c1ccccc1)c1cc(Br)ccc1O)NCC1(c2ccccc2)CCCC1
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?