Cc1sc2cc(-c3cccc([N+](=O)[O-])c3)c(-c3cccc([N+](=O)[O-])c3)c[n+]2c1C.[Br-]
Hydrogen bond acceptor: The atom, ion, or molecule component of a hydrogen bond which does not supply the bridging (shared) hydrogen atom. How many hydrogen bond acceptors does the molecule have?