[（n-C4H9）3SnO2C（CH2）2CO2Sn（C4H9-n）3]：A Novel Three-dimensional Framework Structure of Organotin Complex

The bis(tributyltin) ester of succinic acid was synthesized by the reaction of disodium salt of succinic acid with tributyltin chloride in a molar ratio of 1:2. The crystal structure was determined by X-ray single-crystal diffraction. It belongs to orthorhombic with space group Pccn, a = 20.949(3), b = 17.470(3), c = 20.345(3)A, V= 7446(2)A^3, Z= 8, Dc = 1.242 g/cm^3, μ=1.365 mm^-1, F(000) = 2864, R = 0.0544 and wR = 0.1417. The tin atom is of five-coordination in a trigonal bipyramidal structure by bridging two carboxylate groups in different directions and the resulting structure which contains straight twist large ring channels along the axes of a, b and c is a three-dimensional framework polymer containing two different tin atoms.     

Hitting a Soft Drug with a Hard Nucleophile: Preparation of Esmolol's Metabolite by Treatment with Bis(tributyltin) Oxide

A facile method for the production of esmolol's metabolite in high purity is described. Bis(tributyltin) oxide is used to disrupt esmolol's ester linkage, and hydrolysis is completed by addition of water, which also allows the inorganic side products to be conveniently extracted into ether. Evaporation of the aqueous phase and trituration with ethyl acetate provides the carboxylic acid–amine internal salt as a white, free-flowing powder.     

Biotransformation of butyltin compounds using pure strains of microorganisms

The debutylation of tributyltin chloride by several strains of fungi, yeasts and bacteria is described. Under standard conditions and with low initial concentration of substrate, significant biotic degradation of tributyltin (6–32%) was detected after five days at 28°C. Dibutyltin and monobutyltin were formed in all cases, with higher yields of the latter. Two microorganisms catalysed the transformation of monobutyltin to dimethyltin and trimethytin whereas all microorganisms were able to methylate inorganic tin(IV) to trimethyltin. Our results suggest that tributyltin biodegradation by microorganisms is generally possible, provided sufficiently low concentrations of substrate are used.     

Effects of tin(IV) chloride and of organotin compounds on aquatic micro-organisms

The growth response of the alga Chlorella kessleri and the euglenoid Euglena gracilis has been studied as a model system to determine the effects of a tin salt (SnCl₄·5H₂O) and of some organotin (OT) derivatives, namely tetrabutyltin (TeBT), tributyltin (TBT) and tributyltin oxide (TBTO). Abiotic degradation was studied as well. Cells were exposed to a toxicity series (0–50 μg/mL⁻¹) for the four chemicals in seven-day bioassays. Both microorganisms are tolerant of the inorganic salt, but growth inhibition was significant for all OT compounds, and especially large for TBT and TBTO. Although C. kessleri and E. gracilis are known to be tolerant towards metals and organic chemicals, the present results show that both are sensitive to organotin compounds: the inhibition of the growth was greater for C. kessleri. © 1998 John Wiley & Sons, Ltd.     

Intramolecular cyclization of beta-amino and beta-ammonio radicals: a new synthetic route to the 1-azabicyclo

Treatment of 1-(2-phenylselenoethyl)-1,2,5,6-tetrahydropyridine (15) with tributyltin hydride affords only the product of reduction, demonstrating the reluctance of the 5-hexenyl radical 9 to undergo ring closure. When the nature of the radical is modified, either by introduction of an ester group at C4 or via its quaternary ammonium salt, cyclization occurs readily; while the radical 52 gives an excellent yield of 1-methyl-1-azoniabicyclo[3.2.1.]octyl bromide (55) uncontaminated with the product of reduction, the bicyclic product from 21 is accompanied by some reduced material. Production of the unwanted alkene can be eliminated in the latter by recourse to the quaternary ammonium ester 1-(2-bromoethyl)-4-carbethoxy-1-methyl-1,2,5,6-tetrahydropyridinium bromide (35) which, when exposed to tributyltin hydride, affords a 1:1 endo/exo mixture of 4-carbethoxy-1-methyl-1-azoniabicyclo[3.2.1]octyl bromide (37) exclusively. These results support the demonstration of the powerful polar effect of an ester function when attached to the double bond of a 5-hexenyl system, a property which can be exploited in the case of the radical 58. Treatment of the precursor, 1-(2-bromoethyl)-3-carbethoxy-1-methyl-3-pyrrolinium bromide (60), with tributyltin hydride generates 58 which is found to cyclize with high regioselectivity, affording a convenient high-yielding synthesis of the endo/exo isomers of 3-carbethoxy-1-methyl-1-azoniabicyclo[2.2.1]heptyl bromide 57. The isomeric bicyclo[2.2.1]heptyl ester 63 was not detected. These observations are in accordance with predictions based upon frontier molecular orbital considerations.     

Dissolved butyltins in marine waters of the netherlands three years after the ban

In 1990 the Dutch government banned the use of tributyltin-containing antifouling paint for ships up to 25m long. Concentrations of dissolved (<0.45 μm) tributyltin and its degradation products di- and mono-butyltin were determined in six selected marinas during three consecutive years with a frequency of five times a year, starting in 1990. The highest butyltin concentrations were found in Scharendijke located in the salt water lake Grevelingen: up to 2500 ng dm^?3. In tidal-water marinas butyltin concentrations were in the order of 50–300 ng dm^?3, depending on the boating and dredging activity. In some marinas higher butyltin concentrations were found during the summer period, probably indicating the illegal use of tributyltin-containing antifouling paints. No clear trend of decrease in dissolved tributyltin concentrations in the different marinas has been found. Due to the equilibrium between the butyltins dissolved in the water and the butyltins adsorbed onto the sediment, water concentrations will remain more or less constant.     

Environmental aspects of tributyltin

The tributyltin species, the active ingredient in some antifouling paint formulations, is perhaps the most acutely toxic chemical to aquatic organisms ever deliberately introduced to water. It has been demonstrated to have an adverse effect on shellfish in France and England, and as a consequence the use of tributyltin-containing antifouling paints has been restricted in these countries. Other countries have banned the use of tributyltin-containing antifouling paints or are contemplating restrictions. This article reviews such environmental aspects of tributyltin as methods of analysis, toxicity, environmental occurrence, persistence and fate. Tributyltin concentrations in many locations may be high enough to cause chronic toxicity or harmful effects in some aquatic organisms, and in some locations the tributyltin concentrations may be high enough to be acutely toxic to some organisms. Biological degradation of tributyltin in water and sediment appears to be the most important factor limiting the persistence of tributyltin in aquatic environments. To some degree, then, the persistence of tributyltin in aquatic environments depends upon the nature of the ecosystem. Tributyltin exhibits low-to-medium persistence in water and moderate persistence in sediment. A summary is given of the regulatory status of tributyltin in some countries, and recommendations are made for further research.     

Determination of organotins in natural waters by toluene extraction and graphite furnace AAS

The determination of tributyltin in natural waters by extraction into toluene and graphite-furnace AAS measurement of tin has been investigated. The effect of pH on the extraction of mono-, di- and tributyltin and triphenyltin has been examined and the optimum conditions for the estimation of tributyltin assessed. The AAS performance is greatly improved by using furnace tubes pretreated by soaking in sodium tungstate solution. Such pretreatment is essential if low detection limits are to be attained. Extraction of the tributyltin from aqueous media resulted in a marked signal enhancement (irrespective of the type of furnace tube), which varied according to the nature of the aqueous solution. The enhancement is believed to result from water in the toluene extract activating the tube surface. Methods for the estimation of tributyltin in waters, appropriate for screening samples as part of routine monitoring programmes, are described. With a 1-litre sample, a limit of detection of approximately 4 ng/l. was attained for tin. The relative standard deviation of six replicate analyses of sea-water containing 170 ng/l. tin (present as tributyltin) was 1.5%.     

The fate of triorganotin biocides on incorporation into hypalon paint-based marine antifouling systems:119mSn Mössbauer and 119Sn NMR studies

Incorporation of bis(tributyltin) oxide into a Hypalon paint system results in the formation of tributyltin chloride and a second organotin species, the identity of which remains uncertain. Both compounds are appreciably retained by the dried paint matrix, thereby resulting in marked reduction in the release rate of the tributyltin moiety into aqueous systems. In contrast, tributyltin acetate, tributyltin carbonate and bis(triphenyltin) oxide appear to be incorporated into the paint film in a largely unchanged state. In the case of triphenyltin chloride and triphenyltin acetate, evidence of dephenylation to form diphenyl- and monophenyl-tin compounds has been obtained.     

Synthesis of 2,4-disubstituted piperidines via radical cyclization: unexpected enhancement in diastereoselectivity with tris(trimethylsilyl)silane

A novel approach to 2,4-disubstituted piperidines is reported, involving the radical cyclization of 7-substituted-6-aza-8-bromooct-2-enoates. Cyclization with tributyltin hydride affords the trans piperidines with trans/cis diastereomeric ratios ranging typically from 3:1 to 6:1. Cyclization with tris(trimethylsilyl)silane affords the same products with diastereomeric ratios of up to 99:1 in certain cases. The enhancement in diastereoselectivity results from the selective rearrangement of the minor stereoisomer through a cascade process involving radical cyclization to the piperidine radical, 1,5-radical translocation, and attack of the translocated radical onto the sulfonamide with extrusion of SO2 in a Smiles-type rearrangement. Slower trapping of the piperidine radical by tris(trimethylsilyl)silane compared to tributyltin hydride accounts for the occurrence of the rearrangement cascade in the former case.     

Determination of butyltin compounds in sediments using an improved aqueous ethylation method

We have determined tributyltin and dibutyltin species in various environmental sediment samples (marine, harbour and river sediment) using the in situ aqueous ethylation-gas chromatography-atomic absorption spectrometry method subsequent to extraction by methanol containing O.5M HCl. The present technique provides a significantly lower detection limit than previous methods, so that tributyltin can for the first time be measured in some of the samples. Thus, the method described is well suited for the determination of tributyltin and dibutyltin compounds in sediments with low levels of butyltin species (e.g., Main River, 1.7 ng of tributyltin as Sn/g dry sediment).     

Fungicidal activity of tributyltin alkylsulfate esters

Tributyltin alkyl sulfate esters, e.g. tributyltin dodecyl sulfate, tributyltin hexadecyl sulfate and tributyltin octadecyl sulfate, were synthesized from the reaction of bis(tributyltin) oxide and appropriate alkyl hydrogen sulfates. The resulting tributyltin alkyl sulfate esters were found to exhibit fungicidal activity on Penicillium, Aspergillus and Syncephalustrum species.     

Trialkyltin Compounds as Neutral Carriers for Anions in PVC Liquid Membranes and Complex Formation with Oxoanions

Under the influence of an electric field, trialkyltin compounds of the type R₃SnX behave as electrically neutral carriers for anions in poly(vinyl chloride) liquid membranes. The interaction of tinorganic compounds with oxoanions was studied in organic phase by means of ¹¹⁹Sn-NMR-monitored titrations. In the case of tributyltin chloride, no appreciable amount of complex was formed with hydrogensulfate, whereas dihydrogenphosphate gave rise to a new species. Dioctyltin dichloride and dioctyltin dioctyltin diacetate formed a 1:2 (salt/ligand) complex with hydrogenphosphate.     

Biotransformation of tributyltin chloride in the presence of resting-cell suspensions of pure strains of microorganisms

We describe the degradation of tributyltin chloride by several strains of fungi, yeasts and bacteria under resting-cell conditions in phosphate buffer, with low initial concentrations of substrate. Yields of biotic conversion of tributyltin ranging from 10 to 77% were observed after a five-day incubation at 28°C. In most cases, dibutyltin and monobutyltin compounds and a fraction of volatile products were formed. Volatile tin compounds essentially included derivatives of monobutyltin and traces of other organomethyltins (mono-, di-, and trimethyltins; di- and tri-butyltins), probably as the corresponding organostannanes. Compared with conditions in which the substrate was incubated with growing microorganisms, higher yields of degradation and substantial amounts of volatile products were obtained.     

Synthesis of Stable Multifunctional C-Phosphonio Phosphorus Vinyl Ylides

Trifluoromethanesulfonic acid reacts at 240 K with bis[bis(diisopropylamino)phosphino]diazomethane, 1, affording the corresponding cationic (phosphino)(P-hydrogenophosphonio)diazomethane derivative 2, which eliminates dinitrogen above 250 K, leading to (phosphino)(phosphonio)carbene 3 isolated in 76% yield (mp 88 degrees C). Bis(diisopropylamino)phosphenium salt 5a adds at 240 K to P-chlorodiazomethylenephosphorane 4 giving (phosphino)(P-chlorophosphonio)diazo derivative 6a, which leads, after N(2) elimination, to the corresponding carbene 7a. Addition of potassium tert-butoxide to 3 gives rise to the transient diphosphinocarbene 8, which rearranges into phosphaalkene 9. Sodium tetrafluoroborate, tert-butyllithium, and tributyltin hydride react with 3 to afford P-fluoro-P'-hydrogenocarbodiphosphorane 10, P,P'-dihydrogenocarbodiphosphorane 12, and stannyl-substituted methylene salt 15, respectively. tert-Butyl isocyanide reacts with phosphoniocarbene 3 giving heterocycle 19, whereas with carbene 7 phosphonioketeneimine 18 and bis(diisopropylamino)phosphinonitrile are obtained.     

Radical reduction of cyclic xanthates: Formation of alkenes and/or 1,3-oxathiolanes from 1,3-oxathiolane-2-thiones

AIBN-initiated radical reactions of 5-membered cyclic xanthates, 1,3-oxathiolane-2-thiones, with tributyltin hydride are described. Alkenes are formed at 0.025 M concentration of tributyltin hydride, whereas a higher concentration (0.25 M) gives 1,3-oxathiolanes. A mixture of alkene and 1,3-oxathiolane is obtained by use of intermediate concentrations. Reactions of cis-and trans-4,5-dialkyl-1,3-oxathiolane-2-thiones with tributyltin hydride afford E-alkenes stereoselectively. For an application of this alkene formation reaction, geraniol has been converted to linalool silyl ether in good yield.     

A new synthetic method: Direct replacement of the nitro group by hydrogen or deuterium

The nitro group in tertiary or secondary aliphatic nitro compounds is replaced by hydrogen or deuterium on treatment with tributyltin hydride or tributyltin deuteride, respectively.     

Bis(tributyltin) oxide as a wood preservative: Its chemical nature in timber

Tributyltin compounds have been used for many years as wood preservatives. This study has provided, for the first time, an explanation for the previously reported dealkylation and/or volatilization of the tributyltin species in, and from, timber. Thus ¹¹⁹Sn NMR studies have shown that, on impregnation into timber, bis(tributyltin) oxide, (Bu₃Sn)₂O, is rapidly converted to other tributyltin species, Bu₃SnOX, and that these subsequently undergo disproportionation to Bu₄Sn and Bu₂Sn(OX)₂ compounds. We have additionally demonstrated that Bu₄Sn, so produced, is not persistent in timber and is lost by volatilization. Since the rate of disproportionation of the Bu₃SnOX species should be dependent upon the nature of the X group, it should be possible to affect significantly, if not to stop, this process by the use of alternative tributyltin fungicides, e.g. tributyltin methanesulphonate. However, tributyltin fungicides have been used successfully in wood preservation for at least 25 years. Therefore, it must be concluded that, even after disproportionation in timber, in service, sufficient preservative action is retained to prevent decay of wood under the conditions of natural exposure.     

Determination of Tributyltin in Oysters by Electrothermal Atomic Absorption Spectrometry

Abstract

Graphite-furnace atomic absorption spectrometry for tributyltin in oysters is described. Tributyltin is extracted by n-hexane after digestion with hydrochloric acid. The 3[sgrave] detection limit for tributyltin is better than 0.01 mg Sn/kg. Typical absorbance values are about 0.10 for tributyltin contents as low as 0.03 mg Sn/kg. Tributyltin contents of 29 oyster samples are given.     

An efficient one‐pot access to poly(arylene ethynylene) homopolymers: Use of the Bu3Sn?moiety as a recyclable carrier to introduce the ethynyl unit into the chain

The palladium‐catalyzed Stille coupling of an aromatic diiodide with half an equivalent of tributyl(ethynyl)tin results in a complex mixture containing the diethynylaromatic compound, the iodo(ethynyl)aromatic compound, unreacted diiodide and the tributyltin iodide side product. Addition of LDA to this mixture, while leaving the iodoaromatic moieties unaffected, causes deprotonation of the ethynyl functionalities, which immediately recombine with tributyltin iodide to form a mixture of bis(tributylethynyltin)aromatic, iodo(tributylethynyltin)aromatic, and unchanged diiodide. Being the palladium catalyst still active, it is sufficient to warm up this mixture to obtain the coupling of the tributylethynyltin and iodo moieties resulting in the formation of a poly(arylene ethynylene) polymer. Isolation of the polymer is easily and rapidly achieved by precipitation, while distillation of the mother liquor allows recovery of the tributyltin iodide side product. The latter can be utilized for the preparation of new tributyl(ethynyl)tin, thus allowing a convenient turnover of the tributyltin moiety. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2603–2621, 2000