Ray Investigations of Organotin IV Compounds

RaSnXj type r/s RsSnXj type ns-R2SnXj type RSnX type 

The tetraorganotin compounds, R4Sn, show no tendency to increase their coordination number, owing to their weak, Lewis acidity conferred by the four electron-releasing alkyl groups. It has, however, been claimed (353) that trimethyl(trifluoromethyl)tin forms a 1 1 adduct with hexamethylphosphoric triamide, and that this may be isolated in the solid state. 

If the ligand X2 in a pentacoordinate triorganotin compound is potentially bidentate, such as the anion of l,3-diphenyl-l,3-propanedione or ofiV-benzoyl-N-phenylhydroxylamine, the tin atom is constrained to a cis-RsSnXj type of geometry, e.g., the triphenylstannyl derivatives of 

It is quite probable that, in the monoorganostannatranes, RSnlOCHjjCHjljN, the tin atom also occupies a trigonal, bipyramidal geometry, but with the organic group forced into an axial site (195, 

This configuration has not yet been demonstrated by X-ray studies, perhaps due to the difficulty in obtaining good crystalline samples. Recently, Tzschach reviewed the whole field of intramolecularly pentacoordinate, organotin compounds (198), including the stannatranes. 

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