O=C(N/N=C1/C[C@@H](O)[C@@H](O)[C@H]2[C@@H]1CC[C@@H]1C(=O)N(c3cccc(Oc4ccccc4)c3)C(=O)[C@H]12)OCc1ccccc1
A higher negative pKa value denotes a less powerful acid. What is this molecule's negative pKa value?