Using BrCCCBr, O=C(c1ccccc1)c1ccc(O)c([N+](=O)[O-])c1 to produce O=C(c1ccccc1)c1ccc(OCCCBr)c([N+](=O)[O-])c1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.