Using OCC(F)(F)C(F)C(F)(F)F, O=[Cr](=O)([O-])O[Cr](=O)(=O)[O-] to produce O=C(O)C(F)(F)C(F)C(F)(F)F, please predict the solvent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.