Trialkyltin compounds

The preparation of trialkyltin compounds of lithium, RgSnLi, and their use for preparing the organotin compounds, RaSnR, has been discussed in a previous section. 

The bis(trialkyltin) compounds of mercury are formed when trialkyl-... 

Mechanistic studies have shown that TBT and certain other forms of trialkyltin have two distinct modes of toxic action in vertebrates. On the one hand they act as inhibitors of oxidative phosphorylation in mitochondria (Aldridge and Street 1964). Inhibition is associated with repression of ATP synthesis, disturbance of ion transport across the mitochondrial membrane, and swelling of the membrane. Oxidative phosphorylation is a vital process in animals and plants, and so trialkyltin compounds act as wide-ranging biocides. Another mode of action involves the inhibition of forms of cytochrome P450, which was referred to earlier in connection with metabolism. This has been demonstrated in mammals, aquatic invertebrates and fish (Morcillo et al. 2004, Oberdorster 2002). TBTO has been shown to inhibit P450 activity in cells from various tissues of mammals, including liver, kidney, and small intestine mucosa, both in vivo and in vitro (Rosenberg and Drummond 1983, Environmental Health Criteria 116). 

Reiter, L.W. and P.H. Ruppert. 1984. Behavioral toxicity of trialkyltin compounds a review. Neurotoxicology 5 177-186. 

Snoeij, N.J., A.A.J. Van Iersel, A.H. Penninks, and W. Seinen. 1985. Toxicity of triorganotin compounds comparative in vivo studies with a series of trialkyltin compounds and triphenyltin chloride in male rats. Toxicol. Appl. Pharmacol. 81 2 4-286. 

Other studies involving trialkyltin compounds also show tin is retained in the liver however, alkyl tin compounds are rapidly converted to metabolites. When rats were administered a single oral dose of... 

Trialkyltin compounds have been shown to be effective agriculturally. Tributyltin oxide (III) has insecticidal and fungicidal activity, but generally has not been useful for plant protection due to phytotoxicity and volatility problems. Tricyclohexyltin hydroxide (TCTH, IV) has been an extremely effective acaricide.(3) Developed under the trade name Plictran, this compound was one of the first commercial acaricides. Another trialkyltin compound under development is hexakis (jS > j3 -dimethylphenylethyl)distannoxane (Vendex, V), which is also an effective acaricide. 

It has been observed that quite generally the toxic effects of organometallic compounds are stronger than those of the underlying metal ions. This is particularly true for the antimicrobial effects. The metal tin shows this phenomenon in a rather dramatic way. Whereas scarcely any pronounced biological effect is known for tin, either in the stannous or the stannic form, certain trialkyltin compounds belong to the most active fungicides known at present. 

Here again, a dramatic effect, be it of a different kind, became apparent. Among the trialkyltin compounds, the propyl and butyl derivatives classified themselves at once amongst the most powerful fungicides known. Also the ethyl, pentyl and cyclo-pentyl derivatives showed high activity. 

Whereas the trialkyltin compounds have not succeeded as agricultural fungicides, one particular tributyltin compound, viz. bis (tributyltin) oxide (TBTO) ... 

Caution. Since trialkyltin compounds are generally toxic, it is advisable to perform the synthesis in a well-ventilated fume hood. 

Trialkyltin compounds of the type R3SnX, of which the best studied are the CH3 compounds (X = C104, F, N03, etc.), are of interest in that they are always associated in the solid by anion bridging (8-XI and 8-XII) the coordination of the tin atom is close to tbp with planar SnMe3 groups. When X is RC02 the compounds may in addition be mononuclear with unidentate or bidentate carboxylate groups. 

Some Proteins that Bind Trialkyltin Compounds... 

The catalyst selection for blocked isocyanates depends on the nature of the blocking agent, the desired cure temperature, the polyol structure, and the application. Mono-, di- and trialkyltin compounds are effective catalysts for many blocked isocyanate reactions with hydroxyl compounds. In most solvent-borne coatings, DBTDL is used as a catalyst. 

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