Size-selective reactivity

Electronic structural model. The size selective reactivity of these metal clusters Ts surprisi ng. Certainly the metal cluster are... 

The reactivity of size-selected transition-metal cluster ions has been studied witli various types of mass spectrometric teclmiques [1 ]. Fourier-transfonn ion cyclotron resonance (FT-ICR) is a particularly powerful teclmique in which a cluster ion can be stored and cooled before experimentation. Thus, multiple reaction steps can be followed in FT-ICR, in addition to its high sensitivity and mass resolution. Many chemical reaction studies of transition-metal clusters witli simple reactants and hydrocarbons have been carried out using FT-ICR [49, 58]. 

The Exxon group has also reported reactivities of vanadi um(3e). These are shown in Fig. 3. Again the pattern is size selective but not identical to niobium clusters. Vanadi urn has specific inert clusters like Vg, which is similar to niobium s 8 and 10 but the pattern is better described by an even/odd alternation. This suggests possible analogies with the one electron metals like... 

Gas-phase metal oxide cluster cations have become increasingly interesting because of the possibility that a controlled reaction of size selected clusters might shed some light on condensed-phase catalysts. The possibility of producing small clusters in the condensed phase from deposition of gas-phase clusters has also been a driving force in the study of the reactivity of gas-phase ions. 

Benedetti, E Berti, R Fabrissin, S. Gianferrara, T. Intramolecular ring opening of epoxides by bis-activated carbanions. The influence of ring size on reactivity and selectivity. J. Org. Chem. 1994, 59, 1518-1524. 

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