Monoorganotin Oxides and Hydroxides

The exchange reaction between the Sn-O bond in dialkyltin oxides, R2SnO, and the SnCl bond in organotin halides is discussed in Section 12.4. 

Hydrolysis of monoorganotin compounds can give rise to a wider variety of hydroxides and oxides through a combination of hydrolysis, dehydration, and aggregation reactions,116 but less work has been done in this field. In moist air, ethyl-, butyl- and octyl-tin trichloride are hydrolysed as far as the hydrated hydroxide dichlorides, RSnCl2(OH) 

When the compounds 12-36 and 12-37 are heated they lose water to give glasses with the composition [RSn(0)Cl] , for example [BuSn(0)Cl] , n = 6.123 With three molar equivalents of alkali, complete hydrolysis of the trichlorides takes place to give the stan-nonic acids. From EtSnCl3, HO[EtSn(OH)0] H, n = 3, has been isolated as an infusible solid, but after several weeks, n had increased to 13.8, when the formula approximated to RSn(0)0H.117 From the hydrolysis of octyltin trichloride at room temperature, the dis-tannoxane 12-38 has been isolated, but if the solution is heated under reflux for several hours, the stannonic acid, OctSn(0)OH, is formed.117 

Treatment of Pr1Sn(OH)2Cl. 3/4 H2O in DMF under the same conditions gives the compounds [(PriSn)12Oi4(OH)6]2+ CF2. 3 H20 and [(PriSn)i2Oi4(OH)6]2+ CF2.2 DMF, in which the structure of the cation (12-39) can be viewed as a sphere with an equatorial ring of six square-pyramidal RSn04 units, with polar caps each of three RS11O5 units the presence of the familiar 4-4-4 motif is indicated.118 124 

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The various tri-, di- and monoorganotin hydroxides and oxides that can be obtained by partial or complete hydrolysis of the corresponding halides or carboxylates often behave as catalysts for reactions such as esterification or transesterification, and it is partly with the aim of obtaining better and more selective catalysts that a lot of work has been carried out on these compounds in the past decade.347... 

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