Bis(tributyltin) oxide as a wood preservative: Its conversion to tributyltin carboxylates in Pinus sylvestris

Tributyltin compounds have been successfully used for many years as wood preservatives, although their chemical nature in timber has not been fully elucidated. This study by ¹¹⁹Sn and ¹³C NMR spectroscopy has shown that, on impregnation into Pinus sylvestris sapwood, bis(tributyltin) oxide [(Bu₃Sn)₂O] is rapidly converted to tributyltin carboxylates (Bu₃SnOCO·R) via reaction with components of the wood resin. It is further suggested that the formation of these species is a prerequisite for the known disproportionation reaction which occurs in (Bu₃Sn)₂O-treated timber.     

A study of trialkyltin β-aryl-β-triphenylgermyl propionates

Twenty new compounds of the form Ph₃GeCHArCH₂COOSnR₃ (R = n-Bu, cyclohexyl; Ar = substituted phenyl) have been synthesized. Their structures were characterized by IR and ¹¹⁹Sn and ¹H NMR spectroscopy. The compounds are five-coordinated carboxylate bridged polymers when R = n– Bu; when R = cyclohexyl (Cy) they are four-coordinate. ¹¹⁹Sn NMR measurements of chemical shift for the two series of compounds have shown that there is a good linear relationship for the chemical shift of ¹¹⁹Sn NMR between the tributyltin and tricyclohexyltin propionates, viz. δ¹¹⁹Sn(Bu₃Sn) = 1.0474 δ ¹¹⁹Sn(Cy₃Sn) + 95.8076, n = 5, r = 0.993. The structure of one compound was determined by X-ray diffraction. It exists as a monomeric four-coordinated species in a distorted tetrahedronal geometry.     

Disproportionation of triorganotin species,R3SnX

Triorganotin compounds, R₃SnX, have found extensive use as a biological agents in such areas as agrochemicals, marine antifoulants and timber preservatives. In contrast, di(R₂SnX₂) and tetraorganotin derivatives (R₄Sn) possess less biological activity than do their triorganotin counterparts. It has been shown that disproportionation of R₃SnX species (i.e. to produce R₂SnX₂ and R₄Sn) can occur especially when X is a chelating or bridging group such as oxide, carboxylate, hydroxy ketone or hydroxyquinoline. This process has implications for the industrial applications and analysis of R₃SnX compounds.     

Organotin wood preservatives: Their compatibility with synthetic pyrethroid insecticides

The stability of three synthetic pyrethroids (cypermethrin, deltamethrin and permethrin) to selected tributyltin compounds, Bu₃SnX [where X = OSnBu₃, Cl, O₂CC₆H₅, O₂C(naphthenyl), OSO₂C₂H₅], (Bu₃SnO)₃PO and (Bu₄N) (Bu₃SnCl₂), in toluene solution was investigated by infrared spectroscopy over a 24-week period. It was found that only (Bu₃Sn)₂O reacted with the pyrethroids and that their order of reactivity was cypermethrin>deltamethrin>permethrin. An attempt was made to elucidate the reaction mechanism(s) occurring between (Bu₃Sn)₂O and the pyrethroids by studying mixtures of this tributyltin fungicide with simple model compounds, R¹CO₂R² where R¹=CH₃; R²=CH₂C₆H₅ and R¹=cyclo-C₃H₅ and R²=CH₂C₆H₅.     

An investigation of the efficacy of organotin compounds for the control of the cotton stainer,Dysdercus cingulatus,the mosquito,Anophelese stephensi,and the common house fly,Musca domestica

A series of commercial organotin compounds was screened for efficacy against the three insect species Dysdercus cingulatus (cotton stainer), Anophelese stephensi (mosquito) and Musca domestica (house fly). Tributyltin species in the general order Bu₃SnCl>(Bu₃Sn)₂O>Bu₃Sn(linoleate) were more effective than two triphenyltin compounds. Tricyclohexyltin hydroxide, dimethyltin chloride, phenyltin trichloride and a diethyltin dichloridephenanthroline adduct were less effective.     

Can mono- or di-butyltin chlorides produce tributyltin chloride at elevated temperatures? Implications for applications in chemical vapour deposition

The thermolysis of the butyltin chlorides at 200-300 °C in the liquid phase has been investigated by ¹H, ¹³C, and ¹¹⁹Sn NMR spectroscopy. The stabilities follow the order: Bu₂SnCl₂ > Bu₃SnCl > BuSnCl₃. Only tributyltin chloride showed any evidence of redistribution, giving dibutyltin dichloride, together with metallic tin, butane, and but-1-ene, which would be formed by decomposition of tetrabutyltin. Dibutyltin dichloride decomposed to give mainly butane with no other apparent liquid organotin compound. Butyltin trichloride gave butane, some butene, and metallic tin, and showed no evidence of forming tributyltin chloride by the redistribution reaction, which would have environmental implications for its use in the CVD coating of glass.     

Thermodynamics of metal-ligand bond formation: XVI. Base adducts of some organotin compounds

Thermodynamic data have been obtained by calorimetric titration in benzene solution at 30° for reaction of organotin compounds with Lewis bases; data are reported for forty acid/base systems.Ph₃SnCl forms $\text{1}\text{1}$ adducts of low stability with pyridine (py) or 4-methyl-pyridine (4-mepy). Ph₂SnCl₂, Me₂SnCl₂, Bu₂SnCl₂ and Bu₂Sn(NCS)₂ form simultaneously $\text{1}\text{1}$ and $\text{1}\text{2}$ adducts with py or 4-mepy and $\text{1}\text{1}$ adducts with 2,2′-bipyridine or 1,10-phenanthroline (phen); the enthalpies of formation of the phen adducts are similar to those of $\text{1}\text{2}$ adducts with 4-mepy. With BuSnCl₃ and PhSnCl₃ it was not possible to obtain data for each step in addition of pyridine or 4-mepy. Adduct stabilities increase with increasing chloride substitution and in the order Bu < Me < Ph; adducts of Bu₂Sn(NCS)₂ are more stable than those of Bu₂SnCl₂.Tributylphosphine does not react with Ph₃SnCl but gives $\text{1}\text{1}$ adducts with the other tin compounds; only PhSnCl₃ adds a second molecule of this base. The $\text{1}\text{1}$ adducts are more stable than those with heterocyclic bases. Tributylamine brings about disproportionation of the compounds R₂SnX₂ to R₄Sn and SnX₄NBu₃.     

Speciation and GC retention indices of some organotin compounds in water

Analytical methods have been developed for the quantitative determination of Bu₄Sn, Bu₃Sn⁺, Bu₂Sn²⁺, BuSn³⁺, Me₃BuSn, Me₂Bu₂Sn, MeBu₃Sn, MeBuSn²⁺, Me₂BuSn⁺ and MeBu₂Sn⁺ in water. Organotin compounds are extracted from water with tropolone at 0.1 % in n-pentane, derivatized with n-pentylmagnesium bromide and determined by gas chromatography with flame photometric detection or flame ionization detection. Absolute detection limits are 0.05-0.12 ng and 1.2-13 ng as tin, respectively. The method was applied to the analysis of spiked tap-water containing 0.3-1000 ng cm^?3 of each of the organotin compounds.     

A study of the disproportionation equilibrium for allyldibutyltin(IV) chloride as an approach to understanding the role of organotins in the aquatic environment

The equilibrium: 2 Bu₂(CH₂=CHCH₂)SnCl⇌Bu₂Sn(CH₂=CHCH₂)₂ + Bu₂SnCl₂takes place when the allyltin chloride is stirred in water. This has been chosen as a model to understand the extent as well as the mechanistic pattways of the disproportionation reactions 2 R₃SnX⇌R₄Sn + R₂SnX₂ which are thought to occur in the aquatic environment. The behaviour of Bu₂(CH₂=CHCH₂)SnCl has been studied in various media: water, water-acetone, water-ethanol and water-hexane. It has also been ascertained that Bu₂(CH₂=CHCH₂)SnCI is a product arising at room temperature from the scrambling of Bu₂Sn(CH₂==CHCH₂)₂ and Bu₂SnCI₂ either neat, in organic solvents or also in the presence of water. Equilibrium [1] has been interpreted as arising from a bimolecular interaction between the electrophilic aquo-cation [Bu₂(CH₂=CHCH₂)Sn(H₂O)_n]⁺ and the nucleophilic molecule Bu₂(CH₂=CHCH₂)SnCl. Kinetic studies on R₃SnMe/Me₂SnX₂ (X = Cl, NO₃) systems in alcoholic solvents (R = Me, Et, n-Pr, i-Pr, n-Bu) support the assumption that, in dissociating media, redistribution processes can be promoted by ionic electrophilic species.     

Reversible crotylstannation of carbonyl compounds. Crotylstannation ability of Bu3-nClnSnCH2CHCHCH3 (n = 0, 1, 2) compounds towards acetone and benzaldehyde and 13C NMR characterization

The crotylstannation reaction:

has been found to be reversible. The compounds trans/cis-Bu_3-nCl_n SnCH₂CH= CHCH₃ (n = 0, 1, 2) have been prepared by elimination reactions of organostannoxy compounds,Bu_3?nCl_nSn—O—C(Me)(i-Pr)CH(Me)CHCH2, which were synthesized by means of transalkoxylation between Bu_3-nCI_nSn(OMe) compounds and threo/erithro-2,3,4-trimethyl-5-hexen-3-ol. Under the conditions used the elimination occurs stereospecifically and with complete allylic rearrangement. The ability of the organostannoxy compounds to yield crotyl butylchlorotins via elimination increases in the order, Bu₃Sn—O—C < Bu₂ClSn—O—C < BuCI₂Sn—O—C. In the addition reactions, the sequence of increasing reactivity is Bu₃SnCrot < CIBu₂SnCrot < CI₂BuSnCrot (Crot = crotyl). The ¹³C NMR spectra of the compounds made reveal that the chemical shifts of the allylic carbon atoms are related to the inductive effects of the chloro-substituents.     

The reactivity of tributyltin oxygen compounds with CCl4: Implications for its use as an extraction/reaction solvent

A variety of tributyltin oxygen compounds,(nC₄H₉)₃SnOX where X = Sn(nC₄H₉)₃, C₂H₅, nC₄H₉, C₈H₁₇, CH₂C₆H₅, COCH₃, have been studied in refluxing CCI₄. A reaction was observed to occur where X = C₂H₅, C₄H₉, C₈H₁₇, CH₂C₆H₅, leading to the formation of (nC₄H₉)₃SnCl, CHCl₃ and an aldehyde. Possible reaction pathways are suggested. These reactions have implications for the use of CCl₄ as an extraction/reaction solvent.     

Emission to air of volatile organotins from tributyltin‐contaminated harbour sediments

An analytical method for determining the presence in air of volatile forms (e.g. chlorides) of tributyltin (TBT) and that of methylbutyltins Me _nBu_(4?n)Sn (n = 1–3) was developed and used to establish whether dredged harbour sediments contaminated with TBT served as sources of air pollution with respect to organotin compounds. The method was based on active sampling of the air being analysed and sorption of analytes onto Poropak‐N. Sorbed methylbutyltins were extracted with dichloromethane and analysed by gas chromatography using flame photometric detection. Other butyltins were converted into butyltin hydrides prior to analysis by gas chromatography. It was shown that TBT‐contaminated sediments from Marsamxett Harbour, Malta, placed in 0.5 l chambers through which air was displaced by continuous pumping for 11 days released mainly methylbutyltins, with concentrations (as tin) reaching maximum 48 h mean values of 8.7 (Me₃BuSn), 22.1 (Me₂Bu₂Sn) and 93.0 ng m^?3(MeBu₃Sn) being measured. Other volatile forms of TBT, dibutyltin and monobutyltin were detected in the headspace air, but very infrequently and at much lower tin concentrations (<2 ng m^?3). It was also shown that methylbutyltins dissolved in sea‐water ([Sn] = 0.2 to 400 ng l^?1) were very difficult to exsolve from this medium, even on prolonged evaporation of the solutions using mechanical agitation and active ventilation. The results suggest that emission of methylbutyltins from contaminated sediments probably occurs only from the surface of the material. The environmental implications of these findings in the management of TBT‐polluted harbour sediments are discussed. Copyright © 2002 John Wiley & Sons, Ltd.     

Adhesion properties of poly(hexamethylene diisocyanate) obtained by organotin catalysis

Various organotin compounds were examined as catalysts for the polymerization of hexamethylene diisocyanate (HMDI) for use as an adhesive; (Bu₃Sn)₂O and Bu₂Sn(OCH₃)₂ gave the best results. The lap shear strength of poly(HMDI) with aluminium was 19.9 MPa; with Cab-O-Sil as a filter, it was 27.2 MPa. These values are comparable to those for epoxy adhesives.     

(tBu2SnAsH)2 und (tBu2SnAsH)3: Zwei neue ring-oligomere Stannylarsine

(^tBu₂SnAsH)₂ and (^tBu₂SnAsH)₃: Two Novel Ring-Oligomeric Stannylarsines ^tBu₂SnCl₂ reacts with NaAsH₂ in liquid ammonia to give the four-membered As–H-functional stannylarsine (^tBu₂SnAsH)₂ ( 1 ). The oligomeric six-membered heterocycle (^tBu₂SnAsH)₃ ( 2 ) is obtained by transamination of ^tBu₂Sn(NH^tBu)₂ with AsH₃. The novel compounds are characterized by NMR (¹H, ¹¹⁹Sn) and mass spectroscopy and their molecule structures determined by X-ray crystallography. In the solid state both compounds contain molecules with planar tin-arsenic rings ( 1 : space group P2₁/n, Z = 2; 2 : space group P6₃/m, Z = 2).     

Structure-activity relationship of some pentacoordinated Tributyltin(IV) complexes derived from sterically hindered Schiff bases of heterocyclic β-diketones

Some pentacoordinated tributyltin(IV) complexes of sterically hindered Schiff bases of heterocyclic β-diketones having the general formula Bu₃SnL (where LH = RC:NZC:C(OH)N(C₆H₅)N:CCH₃ where R = –CH₃, –C₆H₅, –C₆H₄Cl (p) and Z = –C₆H₄Cl(m), –C₆H₄Cl(p) and –C₆H₄Cl(p)] were screened for their antimicrobial activity against the bacterial strain (Bacillus subtillis) and fungal strains (Candida albicans and Aspergillas niger). These monomeric pentacoordinated tributyltin(IV) complexes possess six membered ring which provide stability to the complexes. These complexes possess Sn←N bond scaffold which impart biological activity in tributyltin(IV) complexes. Antimicrobial bioassay results reveal that these tributyltin(IV) complexes derived from sterically hindered Schiff bases of heterocyclic β-diketones were possess more inhibition potential than their respective parent ligands. These pentacoordinated tributyltin(IV) complexes may used as antibiotic drug in future.     

Synthesis of poly(phenylsilsesquioxane) having organostannyl groups

Poly(phenylsilsesquioxane) (PSQ) having tributylstannyl groups (TBPSQ) was prepared from phenyltrimethoxysilane and bis(tributyltin) oxide [(Bu₃Sn)₂O] under basic conditions. The procedure, using a catalytic amount of basic reagent such as triethylamine, sodium hydroxide, or aqueous ammonia, afforded yields of TBPSQ based on Si in the range of 12–45% at a number‐average molecular weight precipitated from ethanol of about 3500. In the other procedure, starting from PSQ with (Bu₃Sn)₂O, the incorporation of tributylstannyl groups into PSQ proceeded effectively in the presence of an acid catalyst such as methanesulfonic acid or sulfuric acid, giving TBPSQ in moderate yields of greater than 52%. Dibutyltin oxide, a bifunctional organotin compound, was also used, affording dibutylstannylated poly(phenylsilsesquioxane) (DBPSQ) without crosslinking. The highest ratio of Si and Sn contained in TBPSQ or DBPSQ, prepared under acidic conditions, was Si/Sn = 7/1. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2125–2133, 2001     

三丁基锡羧酸酯的结构表征及其生物活性研究

合成了三十个三丁基锡羧酸酯Bu3SnO2CR(R=烷基、芳基、芳氧甲基和呋喃基)。通过对它们的红外光谱、核磁共振谱(^1^3C, ^1^1^9Sn)的研究, 表明羰基红外吸收频率与锡原子的配位数有密切关系, 同样分子上的微小变化明显地表现在δ119Sn上, 对位取代基苯甲酸酯的δ119Sn与苯环上取代基的Hammett常数(σ)之间存在良好的线性关系:δ119Sn=19.11σ+110.612 n=7, γ=0.9955着重研究了部分化合物在经济作物上的抗病原菌能力, 结果表明, 这是一类具有广谱性的有机锡化合物, 抗菌活性优于对比药剂朴海因, 接近或相当于多菌灵, 它们同时具有较强的除草活性。     

Encapsulation of organotin compounds in metal acetate glasses

Triorganotin halides, oxides and sulphides can be dissolved in molten, mixed-metal acetates at ca 140–160°C without decomposition; quenching provides glasses into which are encapsulated the organotin species. Halide/acetate and oxide/acetate, but not sulphide/acetate, exchanges occur in the melt. Only partial exchange was found for hindered trineophyl tin chloride [(PhCMe₂CH₂)₃SnCl], in contrast to the complete exchanges observed for the butyl (Bu), phenyl (Ph) and cyclohexyl (Cy) analogues. Complete oxide/acetate exchange was found for (Bu₃Sn)₂O, partial exchange occurred for (Cy₃Sn)₂O, whilst no exchange resulted with bis(trineophyltin) oxide or (Ph₃Sn)₂O. Tin–tin bonds (e.g. as in Ph₃SnSnPh₃) and carbon–tin bonds (even the allyl–Sn bond in Bu₃SnCH₂CH?CH₂) are not affected. The acetate glasses dissolve in aqueous media with release of the organotin species and they have potential as slow-release systems which is currently being investigated.     

Polarographic studies on tributyltin oxide in dichloromethane and tetrahydrofuran with application to antifouling paint

In the presence of tributyltin oxide, (Bu₃Sn)₂O, an oxidation process is observed at mercury electrodes in non-aqueous solvents. On the polarographic time-scale, the oxidation involves the mercury electrode and is believed to occur according to the following reaction scheme: 2Bu₃SnOSnBu₃ + 2Hg?[Bu₃SnHgSnBu₃]²⁺ + Hg (OSnBu₃)₂ + 2e^? Hg(OSnBu₃)₂+2Hg?[BuSnHgSnBu₃]²⁺ + 2HgO+2e^? to give the overall process Bu₃SnOSnBu₃+2Hg?[Bu₃SnHgSnBu₃]²⁺ + HgO+2e^?. On the time scale of controlled-potential electrolysis, [Bu₃SnHgSnBu₃]²⁺ is unstable and additional electron transfer occurs. The oxidation process forms the basis of a specific high-performance liquid chromatographic method for the determination of tributylin oxide in antifouling paint. A static mercury drop electrode in the hanging drop mode is used as an amperometric detector in a flow-cell configuration.     

Offenkettige und cyclische As‐funktionalisierte Stannylarsine: Darstellung,Reaktionen und Struktur

Open‐Chain and Cyclic As‐functionalized Stannylarsines: Synthesis, Reactions, and Structure ^tBu₃SnAsH₂ ( 1 ) reacts with MeLi to form the lithium compound ^tBu₃SnAsHLi which reacts with ^tBu₂SnCl₂ to give the AsH‐functionalized bis(arsino)stannane ^tBu₂Sn(AsHSn^tBu₃)₂ ( 2 ). Metallation of diarsadistannetane (^tBu₂SnAsH)₂ ( 3 ) with two equivalents of ^tBuLi yields the dilithio compound (^tBu₂SnAsLi)₂ which reacts with Me₃SiCl or Me₃SnCl to give the corresponding As,As′‐bis‐substituted diarsadistannetanes (^tBu₂SnAsSiMe₃)₂ ( 4 ) and (^tBu₂SnAsSnMe₃)₂ ( 5 ), respectively. The novel compounds are characterized by NMR (¹H, ¹¹⁹Sn) and mass spectroscopy, ring compounds 4 and 5 further by X‐ray structure analysis. In the solid state both ring compounds contain molecules with planar tin‐arsenic rings and two trans‐configurated Me₃Si‐ or Me₃Sn‐ring substituents (space group P2₁/n (No. 14), Z = 2).