Gas‐phase interactions of organotin compounds with glycine

Gas‐phase interactions of organotins with glycine have been studied by combining mass spectrometry experiments and quantum calculations. Positive‐ion electrospray spectra show that the interaction of di‐ and tri‐organotins with glycine results in the formation of [(R)₂Sn(Gly)‐H]⁺and [(R)₃Sn(Gly)]⁺ ions, respectively. Di‐organotin complexes appear much more reactive than those involving tri‐organotins. (MS/MS) spectra of the [(R)₃Sn(Gly)]⁺ ions are indeed simple and only show elimination of intact glycine, generating the [(R)₃Sn]⁺ carbocation. On the other hand, MS/MS spectra of [(R)₂Sn(Gly)‐H]⁺complexes are characterized by numerous fragmentation processes. Six of them, associated with elimination of H₂O, CO, H₂O + CO and formation of [(R)₂SnOH]⁺ (?57 u),[(R)₂SnNH₂]⁺( ?58 u) and [(R)₂SnH]⁺ (?73 u), are systematically observed. Use of labeled glycines notably concludes that the hydrogen atoms eliminated in water and H₂O + CO are labile hydrogens. A similar conclusion can be made for hydrogens of [(R₂)SnOH]⁺and [(R₂)SnNH₂]⁺ions. Interestingly, formation [(R)₂SnH]⁺ ions is characterized by a migration of one the α hydrogen of glycine onto the metallic center. Finally, several dissociation routes are observed and are characteristic of a given organic substituent. Calculations indicated that the interaction between organotins and glycine is mostly electrostatic. For [(R)₂Sn(Gly)‐H]⁺complexes, a preferable bidentate interaction of the type η²‐O,NH2 is observed, similar to that encountered for other metal ions. [(R)₃Sn]⁺ ions strongly stabilize the zwitterionic form of glycine, which is practically degenerate with respect to neutral glycine. In addition, the interconversion between both forms is almost barrierless. Suitable mechanisms are proposed in order to account for the most relevant fragmentation processes. Copyright © 2013 John Wiley & Sons, Ltd.     

Effect of organotin compounds on trout AMP‐deaminases

The comparative toxicity of the organotin compounds tributyltin chloride (TBTC), dibutylin dichloride (DBTC) and monobutyltin trichloride (MBTC) was investigated on 5′ adenylic acid deaminase (AMP‐deaminase) purified from trout skeletal muscle and heart. Treatment with TBTC of both enzymatic forms of AMP‐deaminase rapidly decreases the enzyme activity, and the organotin derivatives DBTC and MBTC have a significant minor inhibitory effect. Differences were observed in TBTC inhibition rate between trout muscle and heart purified enzymes that could be related to the different cellular localization of the two AMP‐deaminases. Copyright © 2001 John Wiley & Sons, Ltd.     

Nanocrystalline F-doped tin dioxide materials: texture, morphology and photosensitization with a perylene-substituted organotin

The controlled hydrolysis of fluoro(2-methylbutan-2-oxy)di(pentan-2,4-dionato)tin followed by annealing at 400-550 °C gave conductive mesoporous F-doped SnO₂ materials. The materials consist of a porous network of aggregated nanoparticles, the mesoporosity observed corresponding to the interparticle space. Tuning of the annealing temperature enabled us to prepare materials with surface areas ranging from 70 to 150 m² g⁻¹, with an average pore size comprised between 50 and 100 Å and with a mean particle diameter ranging from 50 to 120 Å. Resistivities as low as 1-2 Ω cm were measured for the sample treated at 550 °C which contained 2-3 at.% of fluorine. This powder reacted with 3-(6-trihex-1-ynylstannylhexyl)perylene to furnish a dye-sensitized F-doped SnO₂ mesoporous materials. An intensity-dependent photocurrent was produced under blue light illumination using the cavity microelectrode (CME) technique. With an aqueous NaBr solution, the photopotential reaches 700 mV, a value slightly higher than that found for an undoped sensitized SnO₂ powder (∼600 mV).     

Fungicidal and spectral studies of some triphenyltin compounds

In the interest of developing a more effective fungicide to combat Dutch elm disease, our laboratories have synthesized several triphenyltin carboxylates and some 1:1 addition compounds of triphenyltin chloride using 2,3-disubstituted thiazolidin-4-ones as the ligand and screened them in vitro against Ceratocystis ulmi, the causative agent of Dutch elm disease, using a shake culture method. Elemental analyses and spectroscopic data indicate that the structures of the carboxy- lates in the solid state are monomeric with a tetrahedral tin atom with the exception of the furan-2-carboxylic acid derivative, which was found to be polymeric. The triphenyltin chloride adducts are trigonal-bipyramidal with the three phenyl groups in the equatorial plane. Far-infrared data indicate that the three phenyl groups are not co-planar. Screening results for both series of organotins indicate that these two classes of compounds are effective inhibitors of Ceratocystis ulmi, with the adducts having a higher activity. The furan-2-carboxylic acid derivative has a markedly decreased activity compared with the other carboxylates and this is attributed to its polymeric structure. © 1998 John Wiley & Sons, Ltd.     

A study of the antitumor activity of four dibutyltin(IV)-N-arylidene-α-amino acid complexes

This paper reports the activity of four dibutyltin(IV)–N-arylidene-α-amino acid complexes against the National Cancer Institute (NCI) panel of 60 cell lines. The results indicated that three of the organotin complexes (C₁₇H₂₅NO₃Sn, C₁₈H₂₇NO₃Sn and C₂₀H₃₁NO₃Sn) exhibit their highest cytotoxic effect on the NCI-522 (non-small cell lung cancer) cell line. The fourth complex, C₂₁H₂₇NO₃Sn, exhibits its highest cytotoxic activity on the cell line RXF-631L (renal cancer). In general, a low to moderate cellular response was observed for all the organotin complexes, with at least one cell line in each subpanel of cells exhibiting a very low growth inhibition response to all the organotin complexes. The low-responding cell lines included HOP-62 (non-small lung cancer), DLD-1 (colon cancer), SF-539 (CNS cancer), SK-MEL-5 (melanoma), IGROV-1 (ovarian cancer) and RPMI-8226 (leukemia). The results also indicated that the compounds did not exhibit any significant subpanel activity and suggested that the compounds were not active in all the cell lines contained in any subpanel. The low to moderate activity of these compounds across the cell lines was attributed to the presence of nitrogen-bearing ligands which prevented the dissociation of the compound and the subsequent binding to DNA. © 1998 John Wiley & Sons, Ltd.     

The small‐scale preparation and NMR characterization of isotopically enriched organotin compounds

Synthetic methods for the small‐scale laboratory preparation of isotopically enriched dibutyltin dichloride, dibutyltin di‐iodide, tributyltin chloride, tributyltin iodide, diphenyltin dichloride, triphenyltin chloride and triphenyltin iodide have been successfully established. Organotin iodides were prepared from redistribution reactions between tin(IV) iodide and the corresponding tetraorganotin, with the exception of dibutyltin di‐iodide, which was prepared directly from the reaction between tin metal and iodobutane. The development of novel procedures for the dealkylation/dearylation of tetraorganotins by acid hydrolysis produced superior yields of tributyltin chloride and diphenyltin dichloride in comparison with redistribution reactions. Organotin iodide redistribution reaction products were converted to their chloride analogues via the fluoride salts using an aqueous ethanolic solution of potassium fluoride. The insolubility of organotin fluoride salts was exploited to isolate and purify the isotopically enriched compounds, and to prevent losses during the purification procedure. The nuclear magnetic resonance (NMR) spectroscopic study of ‘natural abundance’ and isotopically enriched organotin compounds gave proton (¹H) and carbon‐13 (¹³C) spectra for butyltins, Bu_4−nSnX_n, and phenyltins, Ph_4−nSnX_n (X = I, Cl), allowing the assignment of ­¹H and ¹³C chemical shifts, and ¹¹⁹Sn–¹³C and ¹¹⁷Sn–¹³C coupling constants. The ¹³C NMR spectroscopic analysis of ¹¹⁷Sn‐enriched organotin compounds has allowed the assignment of certain resonances and tin–carbon coupling constants which were previously unobservable. The spectral patterns show that Δ(¹H) and Δ(¹³C) values are sensitive to structural changes, and that ¹³C shielding decreases with an increase in the electronegativity of the substituent. The tin–carbon coupling constants are also sensitive to structural changes, and for alkyl and aryl compounds the couplings decrease in the order ¹J > ³J > ²J > ⁴J. The ¹³C chemical shift values and the magnitude of tin–carbon coupling constants are shown to be solvent‐dependent. The ¹³C spectra of the isotopically enriched compounds show that the degree of isotopic enrichment and the nature of the isotope used (magnetic or non‐magnetic) are reflected in the spectral pattern obtained. Copyright © 2000 John Wiley & Sons, Ltd.     

Organotin contamination,imposex and androgen/oestrogen ratios in natural populations of Nassarius reticulatus along a ship density gradient

Levels of organotin body burden (expressed as tin), imposex and steroid hormones (testosterone, 17β‐oestradiol, testosterone glucuronide and sulfate conjugates) were investigated in natural populations of Nassarius reticulatus in the Ria de Aveiro (northwest Portugal) between 1997 and 1999. The tributyltin (TBT) whole body burden (b.b.) of females presented increasing gradients from the adjacent open coast (16–26 ng g^?1 dry weight (d.w.)) towards the ports inside the Ria de Aveiro (195–272 ng g^?1 d.w.). Triphenyltin b.b. was only detected at the most polluted port (22 ng g^?1 d.w.). Imposex also presented increasing values from the adjacent coast (vas deferens sequence index (VDSI): 0.0–0.5; relative penis length index (RPLI): 0.0–2.4; penis length index (PLI): 0.0–0.3 mm; percentage of affected females (%I): 0–30) towards the ports (VDSI: 3.8–4.8; RPLI: 51–80; PLI: 6.7–10.8 mm; %I: 100). The testosterone levels in females without imposex were always lower than in females with imposex, and the ratio of testosterone/17β‐oestradiol in females tended to increase with increasing imposex and organotin contamination. In spite of the large difference in the female testosterone and 17β‐oestradiol levels between summer and winter, related to the reproductive cycle, the spatial trend of the testosterone/17β‐oestradiol ratio was remarkably similar in shape and values in the two seasons. Imposex was significantly correlated with the TBT b.b. and the testosterone/17β‐oestradiol ratio in females. The testosterone conjugate levels did not show any clear pattern with the increasing values of imposex and TBT contamination. Copyright © 2005 John Wiley & Sons, Ltd.     

The determination of pesticidal and non-pesticidal organotin compounds in water matrices by in situ ethylation and gas chromatography with pulsed flame photometric detection

The concurrent determination of pesticidal and non-pesticidal organotin compounds in several water matrices, using a simultaneous in situ ethylation and liquid–liquid extraction followed by splitless injection mode capillary gas chromatography with pulsed flame photometric detection, is described. The speciation analysis of nine organotin compounds includes low molecular weight–low boiling (non-pesticidal) and high molecular weight–high boiling analytes (pesticidal) of significant environmental interest. The minimum time for sodium tetraethylborate alkylation, using mechanical agitation, is determined to be 15 min in order to ensure the complete derivatization of the entire list of analytes. The utilization of a “hot needle” and a rapid injection rate is shown to be an efficacious means to eliminate “mass” or “needle” discrimination when determining the mixture of organotin compounds. Method detection limits are calculated to be in the low ng L^{− 1} range. The final method is applied to various water samples; storm water from the Cincinnati area demonstrated low native levels of three of the organotin compounds.     

Speciation of tin in sediments and soils by leaching

For the evaluation of the speciation of Sn in solid samples, a leaching sequence is presented, which takes into account the special properties of the element investigated. The sample is leached with ethanol (organics), 25% acetic acid (carbonates), oxalate (coprecipitation upon Fe/Mn-hydroxides), then oxidized with KMnO₄ (sulfides), and finally sublimed with NH₄I (cassiterite); the silicate fraction is found as the difference to the total decomposition value (e.g. LiBO₂).Final determinations are done by hydride AAS from tartaric acid-solutions, except the ethanol fraction which is submitted to ETA-AAS. In the furnace, addition of HNO₃ and H₂O₂ and rapid heating in the gas-stop mode results in equal sensitivity of organic and inorganic tin in the ethanol extract. The proposed method is checked by coprecipitation/adsorption experiments and by addition of tin-bearing minerals to a natural sediment.The method was applied to fresh water sediments. In sediment cores, the KMnO₄ fraction was dominant, whereas in an oxic surface sediment NH₄I releases the main fraction (cassiterite).     

阳离子固相萃取-超高效液相色谱-串联质谱法测定皮革制品中的4种三取代有机锡化合物

建立了超高效液相色谱-串联质谱测定皮革制品中三丁基锡、三苯基锡、双-三苯基锡氧化物、三环锡等4种三取代有机锡化合物(TOT)的方法。采用盐酸溶液提取皮革制品中的有机锡化合物,使其呈阳离子态,经阳离子固相萃取净化,有机锡化合物在超高效C18色谱柱中完成分离,在正离子模式下采用多反应监测模式进行串联质谱测定。三丁基锡、三苯基锡、双-三苯基锡氧化物(以三苯基锡计)的定量限为10 μg/kg,三环锡的定量限为20 μg/kg;分别添加4种待测物于空白皮革样品中,加标回收率为54.1%～101.4%,相对标准偏差为4.3%～9.8%。实验结果表明,该方法简单、灵敏、准确,各项技术指标均满足国内外法规的要求,可用于皮革制品中4种三取代有机锡化合物残留的确证检测。