Dialkyltin compounds

The dialkyltin compounds show a similar trend of decreasing toxicity with increasing length of the alkyl chain, and certain di-n-octyltin derivatives have been used for many years in food-contact applications, as described in Section V. 

It may, therefore, be seen that the mammalian toxicity of the lower dialkyltin compounds, unlike that of their trialkyltin counterparts, is markedly dependent upon the nature of the X groups this is probably true for species other than mammals (e.g., fungi) if the mode of action is similar. 

Dibutyltin diacetate, dilaurate, and di-(2-ethylhexanoate) are used as homogeneous catalysts for room-temperature-vulcanizing (RTV) silicones. The dialkyltin compounds bring about the cross-linking of the oligomeric siloxanes, to produce flexible, silicone rubbers having a host of different uses, such as electrical insulators and dental-impression molds. Recent work has also shown (560) that various dibutyltin dicar-boxylates catalyze both the hydrolysis and gelation of ethyl silicate under neutral conditions. 

Dimethyltin dichloride is used in the glass industry as an alternative to stannic chloride for coating glass with a thin film of stannic oxide 562). The dialkyltin compound vapor is brought into contact with the glass surface at temperatures of 500-600°C, where decomposition and oxidation occurs. 

Table 7 Measured half-lives of dialkyltin compounds in soils. ...

It should be noted that dicyclopentadienyltin does not give any detectable reaction with 2,3-dimehtyl-1,3-butadiene, in contrast to the dialkyltin compound 154). According to Eq. (31) 6- or 9-membered ring compounds are formed. The dicyclopentadienyl compound in Eq. (31) can also be replaced by the unstable stannylens 154). 

Dialkylthallium(III) derivatives, 24 634 Dialkyl thiodipropionates, 3 111-112 Dialkyltin compounds, as PVC stabilizers, 24 821... 

Henninghausen G, Lange P, Merkord J. 1980. The relationship between the length of the alkyl chain of dialkyltin compounds and their effects on thymus and bile ducts in mice. Arch Toxicol (Suppl 4) 175-178. 

Early attempts at producing dialkyltin compounds yielded polymers. More recently, Neumann has found several synthetic routes to reactive R2Sn intermediates which can be trapped by oxidative-addition reactions (J). In the absence of trapping agents the divalent tin compound polymerizes. Lappert and co-workers have shown that the bulky bistri-methylsilylmethyl ligand stabilizes the divalent tin species toward polymerization. This stable divalent tin species thus provides an excellent starting material for investigating a wide variety of oxidative-addition reactions, as shown in Fig. 10 (78). 

Dialkyltin compounds catalyze the preparation of carbamates from aromatic amines and organic carbonates. 

Dialkyltin Compounds. All of the dialkyltin dimercaptides and dicarboxylates were prepared by reaction of the appropriate dialkyltin oxide (Alfa Inorganics) with the desired mercaptan or carboxylic acid. The reactions were carried out in refluxing benzene or toluene using a Dean-Stark water separator. The yields are quantitative and products require no purification (purity confirmed by H and 13C NMR). The dialkyltin dichlorides were obtained commercially (Alfa Inorganics) and used as received ... 

Organic tin compounds Dialkyltin compounds - especially dimethyl-tin and diethyltin dichloride - are dermal irritants, but several of them (e.g., dibutyltin diacetate, dilaurate, maleate, oxide) do not cause such irritation (Lyle 1958). Tributyl and trimethyltin compounds are not allergic dermal and conjunctival irritants, but are responsible for the acute burns that appear several hours after the dermal contact. 

Dermal Effects. Dialkyltin compounds, especially dimethyltin and diethyltin dichloride, are dermal irritants but several of them, like dibutyltin diacetate, dilaurate, maleate, and oxide, are not [42], Tributyl- and trimethyltin compounds are not allergic dermal and conjunctival irritants but are responsible for acute bums appearing several hours after the dermal contact [42]. The lesions last several days, and consist of follicular inflammarion, pruritis, and minute pustules that dry after 2 or 3 days. Recovery takes a week. The hair doesn t seem to be affected. Subacute contacts are responsible for pruritis and scratching lesions, reddening of the skin, and sticky skin. Lesions affect the lower abdomen, thighs, groin, and perineum. Tetraalkyltin compounds applied on the skin have never produced any effect [42]. 

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