O=[N+]([O-])c1ccc2nc(/C(=N/Nc3ccccc3)C(O)c3ccc(C(O)/C(=N\Nc4ccccc4)c4nc5ccc([N+](=O)[O-])cc5nc4O)cc3)cnc2c1
A lower number of negative pKa indicates that the acid dissociates more entirely in water. What is the negative pKa of this molecule?