Tris methyltin

The trialkylstannyl derivatives are obtained directly by reaction of tri-methyltin chloride with 2-lithiooxazole (87S693), but in the case of the silyl compounds an extra step is required, involving the base-catalyzed thermal ring closure of the silylated ring-opened oxazole (Scheme 81)(84CC258 87JOC3413). 

In a final ingenious set of experiments, it was shown35 that addition of tri-methyltin bromide resulted in an increase in the values of but in a marked decrease in the values of "bs (see Table 23). These results are explicable if a complex Me3SnBrBr2 is formed (again in but low concentration), since such a complex would be expected to provide a very active source of electrophilic bromine in the second-order mechanism, through a transition state such as (XV). 

The data obtained, when analyzed as a whole, show that Me3SnBr-DMSO may be the strongest complex among molecular complexes of tri-methyltin halides with monodentate ligands. 

The white solid remaining in the bulb fumes in moist air and is partially hydrolyzed to give an acid solution (HF). It can be identified as a mixture of fluorotrimethylstannane and tri-methyltin hexafluorophosphate.22 The latter substance cannot be isolated as a pure sample. 

An important practical consideration is the choice of the anhydride trifluoroacetic anhydride is quite readily available, but the byproduct tri-methyltin trifluoroacetate is approximately as volatile as MTO, and the usual purification (sublimation) can be quite difficult. However, use of perfluoroglutaric anhydride results in a relatively nonvolatile tin perfluoro-glutarate, allowing for a straightforward isolation of MTO. 

HOMOALLYLIC ALCOHOLS Allyl tri-methyltin. lodomethyltri-n-butyltin. (+)-3-Phenyl-2,3-bornanediol. Tetra-n-butylammonium fluoride. 

The silanetriols 14-16 react with trimethylsilyl chloride in a 1 1 ratio to yield the products RSi(OH)2(OSiMe3) (50-52) respectively [43]. These compounds show monosubstitution of the trisilanol by a trimethylsilyl group. The reaction of silanetriol 15 with GeMesCl in a 1 2 ratio yields the acyclic siloxane RSi(OH)(OGeMe3)2 (53). The reactions of the silanetriols 14-16 with tri-methyltin chloride in 1 3 ratio give the acyclic stannasiloxanes RSi(OSnMe3)3 (54-56) [44]. 

Tributyltin and tributyltin oxide are still used on boats and ships to prevent growth of barnacles. They are extremely toxic for many invertebrates in the sea, notably some snails whose sexual organs develop abnormally. In these snails the female develops a penis. In oysters and other bivalves, their shells become too thick. Tributyltin must be regarded as one of the most serious environmental pollutants, but contrary to the lower analogues, tri-methyltin and triethyltin, they are not very toxic to man and other mammals. Trimethyltin is of considerable interest for neurotoxicologists because it leads specifically to atrophy of the center for short-term memory, the hippocampus. The ethyl analogue has other serious detrimental effects on the brain. 

Harris RK, Siinnetcioglu MM, Fischer RD. Variable-temperature C solid-state NMR spectra mobility of tri-methyltin groups in coordination polymers of the type [(Me3Sn) M(CN)J (M=Fe, Os, Ru). Spectrochim Acta A 1994 50 2069-2078. 

Sodamide in liquid ammonia has also been employed to convert bis(tri-methyltin) oxide and trimethyltin phenoxide into tris(trimethylstannyl)-amine (79). 

However, the reaction of methyltrichlorotin with three equivalents of 1 failed to give the desired tris(undecamethylcyclohexasilanyl)methyltin 4a. 

An improvement was the use of the mixed ester of perrhenic and trifluoroacetic acid, avoiding the chemical loss of rhenium [3, 4]. At the same time, the much less toxic tris(n-butyl)methyltin was used for the selective methylation in eq. (2). This route reached the laboratory pilot-plant stage in 1999. 

Methyltin tris(isooctyl mercaptoacetate) 2525 263-017-4 Dimethyl soyamine 1414... 

Most environmental studies have focused on three distinct groups of OTCs the butyltin, phenyltin, and methyltin compounds. Differences in the chemical nature of the mono-, di-, tri-, and tetrasubstituted OTCs, particularly between the ionic and neutral forms, mean that it is difficult to find extraction methods suitable for all of the species. Extraction of the OTCs prior to their determination is required for air, water, sediment/soil, and biota samples. 

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