Anions organotin

This represents the first synthesis of an anionic organotin(II) derivative it has been characterized by its elemental analysis, NMR, and Mossbauer spectroscopy but the compound s structure is not known (54). 

Organotin(rV) compounds are characterized by the presence of at least one covalent C-Sn bond. The compounds contain tetravalent Sn centers and are classified as mono-, di-, tri-, and tetraorganotin(IV), depending on the number of alkyl (R) or aryl (Ar) moieties bound. The anions are usually CP, F , 0 , OH , -COO , or -S . It seems that the nature of the anionic group has only secondary importance in biological activity. 

In order to avoid the necessity of adding a quaternary ammonium compound to solubilize the organotin derivative, a number of new, anionic, tributyltin salts of the type (RsR P)" (BuaSnClt) , where R = Ri = "Bu or Ph R = Ph, R = Bz, were prepared (440, 536). Although these contain discrete, trigonal, bipyrEimidal tributyldichloro-stannate anions (440), their solubility in water was found to be very low. 

As discussed in section 2, the alkyltin component of organotin compounds is relatively stable to environmental degradation processes such as hydrolysis, compared with the association with the relative ligand (such as an isooctyl mercaptoacetate group). Thus, in water, most of the derivatives are reported to dissociate to the constituent alkyltin (usually as the chloride or the oxide) and the relevant anion (KemI, 2000). 

Crompton [21] has reviewed the use of electrochemical methods in the determination of phenolic and amine antioxidants, organic peroxides, organotin heat stabilisers, metallic stearates and some inorganic anions (such as bromide, iodide and thiocyanate) in the 1950s/1960s (Table 8.75). The electrochemical detector is generally operated in tandem with a universal, nonselective detector, so that a more general sample analysis can be obtained than is possible with the electrochemical detector alone. 

Although this method is not a general procedure, being specific for a-nitroketones, it has several merits to avoid the use of toxic reagents such as organotin compounds. Functionalized ketones have been prepared by this denitration reaction, in which functionalized nitroalkanes are used as alkyl anion synthons. For example, 3-nitropropanal ethylene acetal can be used as synthon of the 3-oxo-propyl anion and 1,4-dicarbonyl compounds are prepared, as shown in Eq. 7.88.135... 

Anionic Rearrangement of Organosilicon and Germanium Compounds, 16, 1 Applications of 9mSn Mossbauer Spectroscopy to the Study of Organotin Compounds,... 

This technique has been used for the determination of polychlorobiphenyls, polychlorodibenzo-p-dioxins, polychlorodibenzofurans, alkyl phosphates, chlorinated insecticides, organophosphorus insecticides, triazine herbicides. Dacthal insecticide, insecticide/herbicide mixtures, mixtures of organic compounds and organotin compounds in soils, and polyaromatic compounds, polychlorobiphenyls, chlorinated insecticides and organotin compounds in non-saline sediments and anionic surfactants in sludges. 

In sludge anionic and non-ionic surfactants carboxylic acids hhydroxybutyrate hydroxy valerate chloroaliphatic compounds chlorophenols polychlorobiphenyls 4-nitrophenol mixtures of organic compounds chlorinated insecticides, phenoxy acetic acid type herbicides and organotin compounds. 

As with the silanes, some of the most useful synthetic procedures involve electrophilic attack on alkenyl and allylic stannanes. The stannanes are considerably more reactive than the corresponding silanes because there is more anionic character on carbon in the C—Sn bond and it is a weaker bond.103 104 There are also useful synthetic procedures in which organotin compounds act as carbanion donors in palladium-catalyzed reactions, as discussed in Section 8.2.3 Organotin compounds are also very important in free-radical reactions, which will be discussed in Chapter 10. 

A very unusual mixed-metal receptor has been prepared by Jurkschat and co-workers [68]. Macrocycle 102 comprises two ferrocene reporter units linked together by two Lewis acidic organotin spacers. Electrochemical measurements in dichloromethane solution show anion-induced cathodic shifts of the ferrocene/ferrocenium redox couple of 130 mV for chloride, 210 mV for fluoride and 480 mV for dihydrogenphosphate. 

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