Mixed diorganotin

Halogen exchange reactions can also be used for the preparation of mixed diorganotin dihalides of the type R2SnXY337 (X, Y = Cl, Br, I) ... 

Keywords Mixed Diorganotin / Diorganosilicon Oxide / Si NMR / " Sn NMR / X-Ray Analysis... 

Tetraorganodistannoxane 11 is in equilibrium with cycto-(f-Bu2SnO)3 (14) and the mixed diorganotin oxides cydo-R2Sn(OSnf-Bu2)20, (15, R = Me3SiCH2), and cycto-f-Bu2Sn(OSnR2)20 (16,... 

Scheme 2.10.5 Two pathways proposed to account for the formation of mixed diorganotin oxides 15 and 16...

However, the use of stoichiometric amounts of molten quaternary halides IGMBr (M = N, P, or Sb) at 120-140 °C leads to excellent yields of trialkyltin bromides (RsSnBr) from alkyl bromides, RBr, and tin powder the alkylation of tin occurs in a stepwise manner and the process can be stopped at the mono- or diorganotin stages and the process can be modified to give mixed trialkyltin bromides (R2R SnBr). 

The Sn CP MAS NMR chemical shift of 4 amounts to -232 ppm, which is 53.5 ppm to lower frequency in comparison with the solution chemical shift. We tentatively attribute this to different conformations in the solid state and in solution. To the best of our knowledge 3 and 4 represent the first completely characterized mixed diorganosilicon/diorganotin oxides. 

The availability of diorganotin dihydrides from the reduction of the corresponding di-oxastannolanes12 renders alkylation of a lithium tin hydride an attractive route to other organotin hydrides with mixed organic groups, R2R SnH.35-36... 

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