Triorganotins

Triorganotins. Triorganotins and diorganotins constitute by fat the most important classes of organotins. 

Table 4. Physical Properties of Typical Triorganotin Halides ...

Table 5. Physical Properties of Commercially Important Triorganotin Compounds ...

Rea.ctlons, The utility of triorganotin chlorides and their appHcation as starting materials for most other triorganotin compounds results from the ease of nucleophile displacement, as indicated in Figure 1. The commercially important triorganotin compounds are most frequendy the oxides or hydroxides, the duotides, and the carboxylates. 

Triorganotin oxides and hydroxides are moderately strong bases and react readily with a wide variety of acidic compounds ... 

This reaction is useful in the preparation of anionic derivatives from the chlorides when the nucleophilic displacement route is unsatisfactory. Even weak acids, eg, phenols, mercaptans, and cycHc nitrogen compounds, can be made to undergo reaction with triorganotin hydroxides or bisoxides if the water of reaction is removed a2eotropicaHy as it forms. 

Prepa.ra.tlon, Triorganotin chlorides of the general formula R.SnX are the basic starting materials for other triorganotins. They are generally prepared by Kocheshkov redistribution from the cmde tetraorganotin ... 

Triben2yltin chloride [3151 -41 -5] is a unique example of a triorganotin chloride that can be prepared directiy from the organic haUde and tin metal ... 

Triorganotin compounds have also been used experimentally in controUed-release formulations to control the infective snail vector in the debiHtating tropical disease schistosomiasis (biHiarzia) and to control mosquitoes in stagnant ponds (103). As yet, the large-scale use of such methods has Htfle support in the host third world countries where these problems are most severe. Tributyltin chloride has been used to confer rodent-repeUent properties on wine and cable coatings (104). 

Diorganotin esters of strong acids are relatively stable to hydrolysis under neutral conditions, but generally, diorganotin compounds ate more reactive chemically than the triorganotins. Diorganotin esters of weak acids are somewhat susceptible to hydrolysis, even under neutral conditions, but this reactivity is moderated somewhat by their hydrophobicity. 

Preparation ndMa.nufa.cture. Monoorganotin haHdes are the basic raw materials for all other triorganotin compounds and are generally prepared by Kocheshkov redistribution from the tetraorganotin, eg, tetrabutyltin or the higher organotin haHdes ... 

Compounds with Tin—Tin Bonds. The most important class of catenated tin compounds is the hexaorganoditins. The ditin compounds are usually prepared by reductive coupling of a triorganotin haUde with sodium in Hquid ammonia ... 

The toxicity of the tetraorganotins has beenUtde studied. Available Hterature indicates that tetrabutyltin and the higher tetraalkyltins are substantially less toxic than triorganotins to mammals if taken orally (175). The high toxicity reported for tetraethyltin (LD g = 9 16 mg/kg) appears to be caused by its rapid conversion in the Hver to a triethyl tin species. 

A series of di- and triorganotin(IV) complexes of 2-thionaphthalene have also been prepared. All the complexes have geometry and moderate biological activities against various bacteria and fungi. 

Diphenic acid (H2A) also forms diorganotin(IV) complexes, which are with two monodentate -COO groups. On the other hand, soluble dinuclear triorganotin(IV) complexes (where the organo moieties are Me and Ph) contain symmetrically bound carboxylates, while the less-soluble compound (cHexsSn) has two asymmetrically bonded carboxylates. All have Tbp structures with [RsSnirV)] units remote from each other. °... 

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