Using BrCCCCBr, COc1ccc(Cn2c(=O)[nH]c3ccccc3c2=O)cc1 to produce COc1ccc(Cn2c(=O)c3ccccc3n(CCCCBr)c2=O)cc1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.