Triorganotin Oxides and Hydroxides

Triorganotin hydroxides and oxides are usually prepared by the hydrolysis of the corresponding chlorides under alkaline conditions. A recent patent reports the formation of trialkyl-, dialkyl-, and monoalkyl-tin oxides by passing an alcohol in the gas phase over tin powder in the presence of a Lewis acid at 200-400 °C,9 for example ... 

Branching at the a-carbon atom appears to confer enough steric hindrance to inhibit dehydration of the hydroxide. Tricyclohexyltin hydroxide, which is used as an acaricide under the name of Plictran, is stable up to about 125 °C when it loses water to give the oxide.3 Tri-t-butyltin hydroxide can be prepared from tris(di-t-butyltin oxide) as shown in Scheme 12-1, and loses water to give bis(tri-t-butyltin) oxide only when it is heated for several horns under vacuum at 200 °C. The properties of some triorganotin hydroxides and oxides are given in Table 12-1.15... 

Listing of symmetric triorganotin hydroxides and oxides continues in Table... 

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. 

In the case of simple amino acids and dipeptides, esterification of the carboxyl groups occurs on heating in toluene with the appropriate bis(triorganotin) oxide or triorganotin hydroxide 481, 482), the water being removed azeotropically. 

In complexes with antibiotics [amoxicillin, ampicillin, methiciUin, penicilUnG, cephalexin and ciprofloxacin (Figure 12.16, a-c)], polymeric compounds may be originated by direct reaction between dialkyltin(IV) chlorides and antibiotic sodium salt, or by direct reaction between trialkyltin(IV) hydroxides and free antibiotic acid. Other combinations (diorganotin oxide/free acid ligand triorganotin(IV) chloride/antibiotic salt) produce monomeric species. 

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

The next major discovery in this field, which was the result of a joint research effort in 1968 between M and T Chemicals, Inc., and the Dow Chemical Company in the United States (475, 524), was that tricyclo-hexyltin hydroxide ("Plictran ) possesses a very high activity against certain types of mites, and this compound was subsequently introduced by Dow as an acaricide for use on apple, pear, and citrus-fruit trees. A second triorganotin acaricide, bis(trineophyltin) oxide ("Vendex or "Torque ), has recently been introduced by Shell Chemical Company (476). Two other tricyclohexyltin compounds are currently under de-... 

The triorganotin oxides and hydroxides are relatively straightforward. The complete structure of trimethyltin hydroxide has not yet been determined, but exposure of a solution of trimethyltin chloride to moisture gives the half-hydrolysis product Me3SnCbMe3Sn0H H20, in which trigonal-planar Me3Sn units are alternately bridged by Cl and OH, with rSnO = 212.5(2) and 212.1(2) pm, and rSnCl = 290.7(3) and 289.2(3) pm (Equation (132)).353... 

The triorganotin species have been used as industrial biocides for over 30 years [117, 118]. Examples are triphenyltin hydroxide (structure 5) for fungal diseases on celery, rice, sugar beets, and coffee tricyclohexylstannyl-1,2,4-triazole (structure 6) as an acaricide for apple, pear, and citrus fruit trees bistributyltin oxide (structure 7) as a wood preservative and tributyltin-methylacrylate monomers (structure 8) polymerized with other acrylates to yield a marine antifoulant polymer that prevents the build of up barnacles, algae, and other marine animals on ships. 

The triorganotin oxides and hydroxides absorb carbon dioxide from the air to give the carbonates, and react with carbon disulfide to give dithiocarbonates, and there are a number of erroneous IR and NMR data in the literature which arise because these reactions were ignored. 

Additional references to triorganotin oxides and hydroxides may be found in Chapters 7 5 8.1 and 9 ... 

Listing of functionally substituted triorganotin oxides and hydroxides continues in Table I67. 

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