Divalent silenes

A third photochemical access to silylenes, beside the isomerization of silenes and the photolysis of tri- or cyclopolysilanes, is the irradiation of geminal diazidosilanes, which under nitrogen loss often gives the corresponding divalent silicon species. However, silan-imines are frequent by-products164 or in some cases even the only products (Section IV). 

A mechanism involving the formation of a divalent silicon (silene) intermediate from an a-elimination of the alkoxy-substituted di- or trisilanes, followed by a series of insertion reactions has been proposed (4). For instance, the thermolysis of 1,2-dimethoxytetramethyldisilane may proceed as follows ... 

In the silicon series there are no suitable divalent compoimds available off the shelf and appropriate silenes must be generated in situ. Reduction of dialkoxydichlorosilanes with magnesium in the... 

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