THE REACTIVITY OF METAL–METAL BONDS: I. THE Sn–Sn BOND

Abstract

The reactions of a series of fluorinated olefins with hexamethylditin have been investigated, under conditions which favor the formation of (CH3)3Sn• radicals. Two principal types of products have been isolated, namely (polyfluoroalkyl)trimethyltin compounds, e.g. (CH3)3 SnCF2CF(R)H, and insertion products of the type (CH3)3SnCF2CF(R)Sn(CH3)3, where R = F or CF3. These results are consistent with the formation of intermediate radicals such as (CH3)3SnCF2C(R)F• which then participate either in hydrogen abstraction or in the formation of the insertion products. Reactions of hexamethylditin with CF2=CFH, CF2=CH2, CF2=CFCl, CF2=CFBr, and C2H4 are also discussed. The direction of attack of the (CH3)3Sn• radical on the olefins indicates that the former has a high degree of nucleophilic character. A more detailed study of the reactions of the cyclic hexamers of dimethyltin and diphenyltin with tetrafluoroethylene shows that some addition does occur, but that the products are of indeterminate composition. The reaction of hexameric dimethyltin with trifluoroiodomethane has also been examined.