Silicon-Transition-Metal Cluster Compounds

Following the many recent developments in the chemistry of metal carbonyl clusters and other metal-metal bonded species, interest has developed in silicon-transition-metal clusters. These will be defined for the present purpose as compounds containing (1) at least one metal-metal bond and (2) at least one silicon atom directly linked to two or more metal atoms. Thus compounds such as Me3SiOs(CO)4Os(CO)4-SiMe3 and R3SiOCCo3(CO)9 are excluded examples of compounds that meet these criteria are shown in Table XXIII. 

A related effect is that silicon-transition-metal compounds, once formed, undergo Si-M bond cleavage when dissolved in polar solvents (252,262,300,305,306,310). The products are often complex, but have been shown to include a cluster compound in one case involving cobalt (252). 

The single-bond compounds between Si, Ge, and Sn and chalcogens (S, Se, Te) are reactive and used as synthetic intermediates in the synthesis of organic compounds, organochalcogen compounds, organo-silicon, -germanium and -tin compounds, and transition metal-chalcogen complexes and clusters. 

Silicon forms a variety of compounds containing clusters of transition metal atoms that exhibit a wide range of structures. DisUane reacts with Co2(CO)g to give the cobalt cluster (38) in which the silicon is coordinated to five Co atoms (equation 48). The Si-- Si distance of 2.817 A is too long for a bond (normally about 2.35 A) and the Si-Co distances average 2.336 A. ... 

---