The Reactivity of Transition Metal Complexes with Dihydrogen

3 THE REACTIVITY OF TRANSITION METAL COMPLEXES WITH DIHYDROGEN 

Even if hydrides of transition metals play an important role as intermediates in catalytic processes such as hydrogenation and hydro-formylation of alkenes and the Fischer-Tropsch reaction,71 in order to follow with the bioinorganic subject, we refer to the interconversion process  

There are several types of hydrogenases, all of which have a metal-containing active site. In fact, they are classified as Fe-only hydrogenases, Ni-Fe hydrogenases and Ni-Fe-Se hydrogenases. 

There is evidence that in the oxidized form, an oxo or hydroxo group bridges the Ni and Fe atoms, which should be absent in the enzymatically active reduced form. 

The Fe-S clusters are believed to act as electron transfer centres for external redox agents such as cytochrome c3 (the high electron transfer ability of metal-sulfur clusters has been discussed in Chapter 8, Section 1, whereas the redox aptitude of cytochromes will be considered in 

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