O=c1cc(CN2CCN(C/C=C/c3ccccc3)CC2)c2cc(O)ccc2o1
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?