O=P1(NCCCn2cc[n+](Cc3nc4ccccc4[nH]3)c2)C=C(c2ccccc2)OC(c2ccccc2)=C1.[Cl-]
The negative base-10 logarithmic of dissociation constant (pKa) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the negative pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the negative pKa value of this molecule?