Silicon-, Germanium- and Tin-Phosphorus Rings

A silicon-phosphorus bond in (Me2PSiMe)3 is readily cleaved by methyl-lithium to generate the acyclic dilithiated derivative Me2Si(PLiMe)2 [10.36, eqn (10.26)]. The related dilithiated dianion Me2Si(PLi Bu)2 has been used to 

Saturated germanium- and tin-phosphorus rings of the type (R2MPR ) (M = Ge, Sn n = 2,3) have been the subject of a limited number of studies. 

A different class of four-membered Su2P2 ring 10.39 is obtained as orange-red crystals from the salt-elimination reaction of potassium di-tert-butyl phosphide with the triethylphosphine adduct of tin(II) dichloride [eqn (10.27)] the dimeric structure was deduced from multinuclear NMR spectra and solution molecular weight measurements. The Sn NMR spectrum exhibits a doublet-of-triplets 

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