Reactivity of Tantalum Hydrides

Overall, the alkene metathesis reaction between 70 and ethene is energetically feasible. The largest free-energy difference between minima and transition states was found to be between the most stable metallacycle intermediate and the transition state for ethene de-coordination, similar to what was computed for the Mo, 

and Re alkene metathesis catalysts. However, the constraints imposed by the bidentate ligand lead to a more complicated pathway that imposes a metallacyclobutane isomerization [105]. 

Reactivity of the Aiumina-Supported, Bisaikyi Alkylidyne Tungsten Catalyst 

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However, over the past decade, advances in, and in particular the availability of sophisticated instrumentation, and in the understanding of the instrumental techniques and the hosts and guests to which they are applied, mean that this need no longer be the case. A recent example in which a gamut of carefully chosen techniques, including such basic but essential measurements as elemental analyses, has led to the same precise characterization of surface species as has been the mainstay of molecular compounds is the study of the synthesis, characterization and reactivity of tantalum hydrides on silica, and their involvement in the dissociation of dinitrogen [203]. 

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