Bridge metal-hydrogen-silicon

Bridged silylene complexes are the subject of a recent comprehensive review by Ogino and Tobita338. These complexes can be classified into three types A, B and C (Scheme 9). In type A complexes there is no metal-metal bonding, the silicon is essentially tetravalent, and the bonding is similar to that in mononuclear metal-silyl complexes. In type C complexes, the bonding is best described as /j2-coordination of the Si—H bond to the metal, or alternatively as a metal-hydrogen-silicon 3-center 2-electron bond. 

Another important class of bridged silylene complexes that should be handled separately is complexes that have hydrogen atoms bridging the metal-silylene bonds C. This bonding can be regarded as a metal-hydrogen-silicon 3c-2e bond, or the r -coordination of Si-H tr-bonds to metals that has been well established for mononuclear complexes.1011 These C-type complexes are now considered to play important roles in the formation of A- or B-type complexes. 

Complexes with Hydrogen-Bridged Silicon-Transition Metal Bonds... 

Formation of Bridged Silylene Complexes with the Hydrogen Atom(s) Bridging the Silicon-Metal Bond(s) (C-Type Complexes)... 

Structure//was one of the first known examples of hydrogen bridges between a transition metal and a main-group element other than boron. There are many interesting features in syntheses, bonding properties, and reactions of silicon-transition-metal compounds which can only be outlined in this article, which covers the literature up to 1973. But any survey achieves its aim if it stimulates further interest and research in its specific area. 

Bulky alkyl groups CH2R (R = Ph, CMca, SiMe, or CMo Pli), which have no hydrogen atoms attached to the carbon or silicon atom in the p position, have been widely used to probe the alkyl chemistry of transition metals Uieir bulk protects the metal from nucleophilic attack, while the absence of 3 hydrogen reduces the risk of decomposition by metal hydride formation and alkene elimination. The use of such ligands attached to manganese has provided examples of hypercarbon atoms bridging pairs of metal atoms that are worthy of brief mention here. 

D. Hydrogen-bridged Transition Metal-Silicon Bonds. 290... 

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