Solid-gas reactions involving lightly stabilized transition metal clusters

4 Solid-gas reactions involving lightly stabilized transition metal clusters 

The observation that it is possible to generate coordinatively unsaturated, highly reactive organometallic species in situ by the use of saturated derivatives contain- 

When Os3(CO)ii(NCCH3) or Os3(CO)n(C2H4) is reacted with CO (1 atm) at 80 °C the pale yellow powder of Os3(CO)i2 formed is easily characterized by C solid-state NMR. The minor line broadening observed for the C resonances of Os3(CO)i2 obtained from these solid-gas reactions, compared with the published spectrum of the recrystallized complex,[ appears to be associated with the powdery nature (microcrystals) of the product. 

According to a dissociative reaction pathway one would expect preferential coordination of the incoming CO ligand at the same site as that occupied by the leaving group. Interestingly, the C MAS spectrum (Fig. 6) shows that CO is equally distributed over axial and equatorial sites when both Os3(CO)n(NCCH3) 

Axially vacant Os3(CO)n was observed by Wrighton et al. as the product of a photoreaction of Os3(CO)i2 in hydrocarbon glass at T IlOK rearrangement of the vacant coordination site has been proposed to explain the experimental reactivity. 

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