Mixed-metal clusters photolysis

Many metal clusters have been prepared by reactions that do not fall into any of the above categories. Space does not permit a discussion of all of these, but we shall illustrate a few by examples. Somewhat surprisingly, photochemical techniques have only been used to produce two mixed-metal clusters, and these were prepared by Sheline and co-workers (66, 109) by photolysis of mixtures of M2(CO)i0 (M = Tc, Re) and Fe(CO)s, Eqs. (47) (66) and (48) (109). 

In addition to the tripodal amido ligand, the chelating amido ligand-stabilized Zr complex was also employed to prepare a Ru-Zr mixed-metal cluster 6 which was converted into the dinuclear complex 7, as shown in Scheme 2. UV photolysis (A>420nm) of the Ru dimer GpRu(CO)2 2 with [Gp2Ti(OBu )] in toluene at —10°G yielded the dinuclear complex [RuTi(OBu )Gp3(GO)2] 8. The reaction also took place in the dark or upon heating. ... 

There are still only a few examples of mixed metal-transition metal clusters containing boron atoms. The first to be reported was Cp2Co2Fe(CO)4B3H3 (92). This cluster results from the photolysis of 2-CpCoB4Hg [a basally substituted isolobal analog of pentaborane(9)] with Fe(CO)5. NMR spectroscopic data are consistent with the proposed structure shown in Fig. 17. 

Photoreactions can also be used to both synthesize and fragment mixed-metal oligomers and clusters. An example of such a transformation is the photochemical extrusion of mercury from the heterotrimetallic cobalt-mercury cluster complex HgCo2(CO)8. Photolysis into the MMCT transition of HgCo2(CO)g results in the formation of cobalt carbonyl, Co2(CO)g, and elemental mercury ... 

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