Trisubstituted organotins

The organotins have a wide range of uses, which are largely specific for the different organotins. Thus, mono-and disubstituted organotin compounds are not suitable as biocides, and trisubstituted organotin compounds are not suitable as PVC stabilizers. 

Similarly, while the main products used as stabilizers in PVC are mono- and disubstituted compounds, owing to the chemistry involved in their production, trisubstituted organotin compounds will comprise a small fraction of the total amount. This could be significant in assessing the toxicity of the compounds (see below). 

Trisubstituted organotins are useful biocides in agriculture and industry. They function as fungicides, bactericides, antihelminthics, and rodent repellents (WHO 1980). Tributyltins are used as antifoulants in marine paints but are restricted by the Organotin Antifouling Paints Control Act (June 16, 1988) which limits the type of vessel on which these paints can be used and sets acceptable release limits (U.S. Bureau of Mines 1989). Bis(tributyltin)oxide is used as a preservative for wood products, leather, ropes, fabrics, and paper. 

The readily available organotin compounds include trisubstituted tin hydrides (stannanes) and chlorides. Trialkylstannanes can be added to carbon-carbon double and triple bonds. The reaction is normally carried out by a radical-chain process.86 87 88 Addition is facilitated by the presence of radical-stabilizing substituents. 

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