Using C[Si](C)(C)CCOCn1ncc2c(c(CBr)c(Br)n2COCC[Si](C)(C)C)c1=O, OCCF to produce C[Si](C)(C)CCOCn1ncc2c(c(COCCF)c(Br)n2COCC[Si](C)(C)C)c1=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.