The Organo Di- and Polysilanes

If aminoorganosilanes contain reactive groups in their organic substituents, the above reaction may produce cyclic compounds, e.g. in the preparation of 2,2,2,2-tetracarbonyl-1,1,3,3-tetramethyl-l,3,2-phosphasilamanganolane [473] (62% b.p. 80°C at 0.13 Pa = 0.001 mm Hg) according to Eq. 3.253  

Bis(trimethylsilyl)mercury and pentacarbonyliron react to form bis(trimethyl-silyl)tetracarbonyliron [474] (36 /o m.p. 68°C) 

Like organic carbon, organic silicon can be catenated. Linear methyl polysilanes with up to 24 silicon atoms are now known, and organocyclopolysilanes with as many as 35 silicon atoms in a single ring have been characterised. 

With a bond strength of 284kJ/mol [475, 476], the Si—Si bonding energy is intermediate between that of the C—C bond (346 kJ/mol) and the Ge—Ge bond (249 kJ/mol). 

Linear alkyl di- and polysilanes with small organic groups and few Si atoms are liquid the other di- and polysilanes are solids and melt, for the most part, without decomposition. For example  

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