| Compounds having the formula Cp*M(NO)2CF3 (Cp* = η5-C5Me5, M = Cr, Mo, W) were synthesized and characterized. The stability of compounds having the formula Cp*M(NO) 2CF3 is observed to diminish in the order Cr >> Mo > W. In addition, a direct comparison of the thermostability of Cp*Cr(NO)2CF 3 and CpCr(NO)2CF3 indicated that the Cp* derivative is only marginally more stable than its Cp counterpart. This is the first direct comparison of trifluoromethylated compounds that indicate results contrary to widespread expectation that Cp* complexes are significantly more stable than their Cp counterparts because of their increased electron donating ability. Collectively, the characterization data of the Cp*M(NO)2CF 3 complexes show good agreement with the experimental observation that this series of Cp* complexes is not significantly more stable than its Cp counterpart.; The first example of a compound known to contain both a trifluoromethyl ligand and an η7-cycloheptatrienyl ligand, (η 7-C7H7)Mo(CO)2CF3(glyme), was isolated. Although (η7-C7H7)Mo(CO) 2CF3(glyme) demonstrates much greater stability than its methyl or phenyl counterparts, it is significantly less stable than the η 5-cyclopentadienyl derivative, (η5-C5H 5) Mo(CO)3CF3. Characterization data from (η 7-C7H7)Mo(CO)2CF3(glyme) indicate that the additional electron density imparted by the η 7-C7H7 ring results in a longer, weaker, and more reactive C-F bond than that observed in the Cp derivative.; Pentavalent antimony species having the formula Sb(CF3) 3X2 (X = F, Cl, Br) were synthesized at low temperatures by reaction of Sb(CF3)3 with XeF2, Cl 2, and Br2, respectively. The thermal stability of these compounds is observed to diminish in the order Sb(CF3)3F 2 ≈ Sb(CF3)3Cl2 > Sb(CF3) 3Br2 >> Sb(CF3)3I2. In addition, Sb(CF3)3F2 was discovered to be a more powerful fluorinating agent than SbF3, SbF5, or a combination of SbF3/SbF5.; Attempts to synthesize Sb(CF3)5 via ligand exchange reactions between Sb(CF3)3Cl2 and Cd(CF 3)2(glyme) resulted in the first compound known to have more than four trifluoromethyl ligands surrounding its central atom. A combination of 19F NMR data, mass spectral data, and solubility data suggest that one product of this reaction could be the ionic compound [Sb(CF 3)4]+[Sb(CF3)6] −. |
