Reductive elimination from polyhydrides

Photoinduced reductive elimination of from polyhydride complexes, HxMLn (x > 3) can, in principle, lead to the generation... 

Table 1. Photoinduced Reductive Elimination of from Di- AND Polyhydride Complexes ...

Hydrides The second most common photosubstitution is the extrusion of H2 from a di- or polyhydride. This reaction was discovered in the case of the yellow crystalline complex, CP2WH2 (Eq. 4.54). This is most probably the result of the promotion of an electron into the M—L a orbital corresponding to the MH2 system. Sometimes the reductive elimination product is stable, or as in Eq. 4.54, it can also be very unstable and can oxidatively add to C—H or other bonds in the solvent or ligands. 

These reactions involve the reductive elimination of hydrogen from both dihydride and polyhydride complexes. For polyhydrides it is found that the photolysis reactions involve either a single or a multiple loss of H2. In some cases the reductive elimination of H2 results in the formation of a coordinate unsaturated complex, but in other cases the photolysis is carried out in the presence of a coordinating ligand that complexes to give a coordinately saturated complex as the final product. 

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