Reactivities of metallo-carbohedrenes: Evidence that V8C12+ has T-d or D-2d symmetry

The metallo-carbohedrene V8C12+ is Studied using a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer coupled to a compact supersonic source. Its reactions with water, ammonia, ROH (R = CH3, C2H5, C3H7, C4H9), and CH(3)X (X = Cl, Br, I) are reported. For polar molecules, sequential attachment reactions occur leading to the initial buildup of the product V(8)C(12)L(4)(+). V(8)C(12)L(5-7)(+) peaks for ammonia and alcohols are also observed, bur, they grow in slowly. These results provide evidence that the geometric structure of V8C12+ is the theoretically,calculated more stable T-d or D-2d symmetry with two sets of metals, as opposed to the T-h symmetry with all eight equi valent metals. In reactions with methyl halide, CH(3)X (X = Cl, Br, I), V8C12+ undergoes four sequential halide abstraction reactions, exclusively, yielding mass spectra that truncate sharply at V(8)C(12)X(4)(+). Dehydrogenation is observed for the secondary reactions with water and alcohols, ROH (R = H, alkyl), yielding V8C12(OR)(2)(+) intermediates. The results from this study are compared to those of other met-cars.