Effects of tributyltin(IV) chloride on the gametes and fertilization of Ascidia malaca (Ascidiacea: Tunicata)

Ascidia malaca gametes before fertilization incubated in 10^?5 or 10^?7 M solutions of tributyltin(IV) chloride, TBTCl, for 3 h appear highly damaged under transmission electron microscopy observation. Also, the fertilization process is affected by the compound: the damaged spermatozoa are present in the vitelline coat and the egg does not cleave. An increase of microbodies, structurally similar to peroxisomes, have been detected in the egg peripheral cytoplasm, probably in relation to their role in alleviating damage to some cellular components. The results have shown that the reproduction of ascidians under unfavourable environmental conditions is prevented. Copyright © 2003 John Wiley & Sons, Ltd.     

Effects of tributyltin(IV) chloride exposure on early embryonic stages of Ciona intestinalis: In vivo and ultrastructural investigations

The effects of tributyltin(IV) chloride (TBT chloride) solutions on ascidian embryos of Ciona intestinalis have been tested at different stages of development. It has been observed, in vivo, that TBT chooride inhibited cleavage of fertilized eggs and of embryo blastomeres giving rise to cellular masses that are not delimited by plasma membrane. Electron-dense precipitates of TBT chloride, probably as inorganic tin, have been observed by transmission electron microscopy in the egg cytoplasm of cellular masses. The same type of precipitate was present also inside the mitochondria, whose structure appeared to be highly modified. These ultrastructure aspects are indicative of a degenerative process of the embroys after incubation in TBT chloride.     

Organometallic complexes with biological molecules: XVI. Endocrine disruption effects of tributyltin(IV)chloride on metamorphosis of the ascidian larva

The effects of tributyltin(IV)chloride (TBT) on the metamorphosis of ascidian larvae of Ciona intestinalis, 2 h after hatching, were investigated. Ascidians are protochordates that lack thyroid follicles and possess thyroid hormones (THs) and their precursors, 3‐monoiodo‐tyrosine (MIT) and 3,5‐diiodo‐tyrosine (DIT), in their endostyle. According to recent findings, these hormones are also present at larval stages, localize in mesenchymal cells and their function seems to be mainly related to larval transformations. Here, we investigate the effects of TBT on thyroxine (T₄) content and localization by exposing larvae of C. intestinalis for different times to TBT concentrations known to block metamorphosis. The result is a blocking of the retraction of the tail, and larval immobility. As detected by immmunohistochemistry, in normal larvae, T₄ is found in all mesenchymal cells spread out in the body cavity, under the adhesive papillae and around the intestine. By contrast, in larvae exposed to 10^?5 M and 10^?7 M TBT, T₄ is detected only in 5% and 25% of total mesenchymal cells respectively. Radioimmunoassay shows a 70% decrease of T₄ content in TBT‐exposed larvae, with respect to unexposed larvae. In addition, neosynthesis of THs is inhibited. Even if parallelism does not exist between the endocrine systems of invertebrates and vertebrates, however, a close similarity exists for functions such as reproduction and metabolism. Our results indicate that TBT could behave as an endocrine disrupter (ED) in ascidians and could impair T₄ metabolism. These findings suggest that the ED activity of TBT could be conserved from invertebrates to vertebrates. Copyright © 2001 John Wiley & Sons, Ltd.     

Effects of tributyltin(IV) chloride on fertilization of Styela plicata (Ascidiacea: Tunicata): II. Scanning and transmission electron microscopy studies

The morphological aspects of Styela plicata fertilization after treatment with tributyltin(IV) chloride are described by means of scanning and transmission electron microscopy investigations. Alterations have been shown both on female and male gametes; spermatozoa, all the egg envelopes and the mitochondria of the egg cortical cytoplasm are modified in relation to incubation time. As a consequence, the damage to gametes blocks sperm–egg interaction and fertilization does not occur. Copyright © 2003 John Wiley & Sons, Ltd.     

Degradation of tributyltin chloride in water photoinduced by iron(III)

The degradation of tributyltin chloride (TBT) photoinduced by iron(III) was investigated. Upon irradiation at λ_excitation >300 nm a photoredox process was observed, yielding iron(II) and ^·2OH radicals. The disappearance of TBT was proved to involve only an attack by ^·2OH radicals: the quantum yield of TBT disappearance was determined. A wavelength effect was observed; the shorter the excitation wavelength, the higher the rate of TBT disappearance. Most of the photoproducts were identified and the mechanism of degradation was elucidated. The main route to degradation is a stepwise debutylation of TBT to di‐ and mono‐butyltin with final formation of inorganic tin. The complete mineralization of TBT was achieved with long irradiation times, leading to innocuous inorganic tin. Copyright © 1999 John Wiley & Sons, Ltd.     

Interaction of tin (IV) chloride with sulfolane and between tin (IV) chloride and lithium chloride in sulfolane solution

Tin (IV) chloride reacts with sulfolane (S) to form a cis-octahedral adduct SnCl₄·S₂. Solutions of lithium chloride and tin (IV) chloride in sulfolane contain the complex ions SnCl ₅ ^– and SnCl ₆ ^2– at 11 and 21 mole ratios of constituents, respectively. The complexes are characterized by conductimetry and by Mössbauer, IR, and Raman spectroscopy.     

Synthesis,characterization and antimicrobial activities of triorganotin(IV) complexes with azo-azomethine carboxylate ligands: crystal structure of a tributyltin(IV) and a trimethyltin(IV) complex

Triorganotin(IV) complexes with polyaromatic azo-azomethine carboxylate ligands viz. 2-{4-hydroxy-3-[(2/4-hydroxyphenylimino)methyl]phenylazo}benzoic acids [H₃L¹/H₃L²] were synthesized by reacting the ligands with either bis-tri-n-butyltin(IV) oxide (for 1 and 4) or trimethyltin(IV) chloride in presence of triethylamine (for 2 and 5) or triphenyltin(IV) hydroxide (for 3 and 6). The complexes were characterized by elemental analysis, UV, IR, NMR, and mass spectrometry. NMR spectroscopic studies of the compounds suggested that the complexes adopt four-coordinate tetrahedral geometry around tin in solution. Molecular structures of 1 and 2 were determined by single-crystal X-ray diffraction. Both complexes have distorted trigonal bipyramidal geometry around tin in the solid state. Compound 1 is a one-dimensional (1-D) double chain coordination polymer which can be described as two different 24- and 30-membered non-porous macrocyclic rings constructed from two tributyltin units and two ligand moieties. The structure of 2 comprises a discrete cyclic centrosymmetric dimer with two lattice water molecules per formula unit. In the dimer, two trimethyltin entities are bridged by two ligand moieties. The dimers are further interconnected with lattice water molecules by multiple O–H?O hydrogen bonds to form a 1-D H-bonded network. The complexes were also screened for their antimicrobial activities.     

Comparison of the acute toxicity of tributyltin and copper to veliger larvae of Nassarius reticulatus (L.)

The ban on the use of tributyltin (TBT) is promoting an increasing use of copper as an active biocide in antifouling paints, with consequent rising levels of this metal in the environment. This study assesses the acute toxicity of copper and tributyltin to the larvae of the mollusc gastropod Nassarius reticulatus. Recently hatched veligers were exposed to nominal TBT‐Sn concentrations of 0.9, 1.4, 1.9, 2.8, 3.8, 4.7 and 5.6 µg l^?1 and nominal copper concentrations of 9.4, 23.4, 46.9, 70.3, 93.8, 117.2, 140.6 and 164.1 µg l^?1 for up to 96 h, under static conditions (17 ± 1 °C and 33 ± 1 psu). The percentage of larval mortality was determined for each organometal/metal concentration and exposure time (1, 24, 48, 72 and 96 h). Both TBT and copper had a highly significant effect on larvae survival (p < 0.001) for all times of exposure, except for the first hour in the particular case of TBT. The lowest observed effect concentration for TBT‐Sn decreased over time from 3.8 µg l^?1 at 24 h to 1.9 µg l^?1 at 96 h, whereas for copper it remained constant over time (46.9 µg l^?1). The median lethal concentration (LC₅₀) for TBT‐Sn decreased from 4.87 µg l^?1 at 24 h to 1.78 µg l^?1 at 96 h, and the LC₅₀ for copper decreased from 83.08 µg l^?1 at 24 h to 58.84 µg l^?1 at 96 h. TBT is far more toxic to N. reticulatus larvae than copper. However, owing to the higher copper environmental concentrations, the risk factors of the two biocides may approach each other. This stresses the need to find adequate substitutes for organotin biocides in future antifouling paints. Copyright © 2005 John Wiley & Sons, Ltd.     

On the hydrolysis of the titanium(IV) ion in chloride media

Determinations of the [Ti(IV)]/[Ti(III) ratio in solutions of titanium(IV) chloride equilibrated with H₂(g), at 25°C in 3 M (Na)Cl ionic medium, have indicated the predominance of the Ti(OH)₂²⁺ species in the concentration ranges 0.5 ? [H⁺] ? 2 M and 1.5 x 10^?3 ? [Ti(IV)] ? 0.05 M. From the equilibrium data the reduction potential has been evaluated Ti(OH)₂²⁺ + 2 H⁺ + e ? Ti³⁺ + 2H₂O, E_oH = (7.7 ± 0.6) x 10^?3 V. The acidification reactions of Ti(OH)₂²⁺ were also studied in 12 M(Li)Cl medium at 25°C by measuring the redox potential of the Ti(IV)/Ti(III) couple as a function of [H⁺]. The potentiometric data in the acidity range 0.3 ? [H⁺] ? 12 M have been explained by assuming Ti⁴⁺ + e ? Ti³⁺, E_o = 0.202 ± 0.002 V Ti⁴⁺ + H₂O ? TiOH³⁺ + H⁺, log K_a1 = 0.3 ± 0.01 Ti⁴⁺ + 2H₂O ? Ti(OH)₂²⁺ + 2H⁺, log K_a1K_a2 = 1.38 ± 0.05.     

Investigations on poly(vinyl chloride). IV. Effects of metal chlorides on the thermal decomposition of poly(vinyl chloride)

The effects of various metal oxides upon the thermal decomposition of poly(vinyl chloride) (PVC) were previously reported. In this work, 23 metal chlorides were investigated to determine their effects on the thermal decomposition of PVC by pyrolysis–gas chromatography at 500°C. Each metal chloride exhibits influences on the course of thermal decomposition of PVC almost similar to the corresponding metal oxide except for a few elements; the metal chlorides from acidic metal oxides accelerate the thermal decomposition of PVC, but the metal chlorides from basic metal oxides do not. On comparing the effects of metal oxides and metal chlorides on the thermal decomposition of PVC, most metal chlorides were found to accelerate the thermal decomposition of PVC more than the corresponding metal oxides, owing to ease of addition of the chlorine atoms released from metal chloride to the dehydrochlorinated chains. It is concluded from these results that the thermal decomposition of PVC containing metal salts is markedly influenced by the ease with which chlorine atoms are released from the corresponding metal chloride.     

Organometallic complexes with biological molecules. XV. Effects of tributyltin(IV)chloride on enzyme activity,Ca2+, and biomolecule and synthesis in Ciona intestinalis (Urochordata) ovary

Considerable attention has been given in recent years to the possibility that xenobiotics in the environment may affect reproduction in animals. In this study, the relative impact of tributyltin(IV) (TBT) chloride, one of the most toxic environmental pollutants, was investigated using Ciona intestinalis ovary as a model system. The pleiotropic effects of TBT exposure are concentration dependent and include a decrease of ATP levels, lipid content and nucleic acid content and synthesis. In contrast, a marked increase in calcium (Ca²⁺) and glucose content is observed. Furthermore, TBT alters enzymatic activity, inhibiting creatine kinase and stimulating alkaline phosphatase and cholinesterase (at concentrations higher than 10^?5M in sterile sea water solution). The implications of these effects on reproduction and embryonal development are discussed, along with the possibility that they reflect an extreme cellular defence mechanism triggered to avoid deleterious consequences for the survival of the species.Copyright © 2001 John Wiley & Sons, Ltd.     

Synthesis of the alkaloids julandine and ipalbidine-use of silicon (IV) chloride

Titanium (IV) chloride and silicon (IV) chloride with high oxygen affinity are the best Lewis acid catalysts, of a number tested, for cyclisation of an enamine-ketone (1) leading to the alkaloid, julandine (2); cyclisation of (6) in methanol solution without catalyst yields $\text{O}$-methylipalbidine (7) .     

Search for triorganotins along the Mar del Plata (Argentina) marine coast: finding of tributyltin in egg capsules of a snail Adelomelon brasiliana (Lamarck, 1822) population showing imposex effects

Cases of imposex were clearly identified in Adelomelon brasiliana living in the Mar del Plata (Argentina) coastal area; percentages as high as 50.0% were determined among the samples studied. These were the first reported cases of ocurrence of imposex in this type of gastropod. Since this is one of the known tributyltin (TBTs) effects, and no previous reports of determination of TBTs in gastropods eggs were found, methods were developed for the speciation and quantitative determination of organotins in A. brasiliana egg capsules. Determination of organotins in samples collected in the Mar del Plata area showed contents of tributyltin chloride (TBT) as high as 400 ng l^?1 in water and 6.50 µg g^?1 in sediments of areas of intensive boat traffic. The results showed the presence of TBT in the egg capsules of A. brasiliana at three different instars (range 0.264–1.86 µg per egg). As far as we know, this is the first report of the finding of TBT in gastropod egg capsules. Copyright © 2004 John Wiley & Sons, Ltd.     

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.     

Effect of Cetylpyridinium chloride on the electron transfer reactions of acetophenones with Ce(IV)

The kinetics of electron transfer reactions between acetophenones with Ce(IV) have been studied in aqueous acetic acid medium in the presence of cationic micelle Cetylpyridinium chloride (CPyCl) at different temperatures. Kinetic data reveal first-order dependence with respect to each of Ce(IV) and acetophenones. The cationic micelle, Cetylpyridinium chloride enhances the oxidation reactions. The catalysis fits to a model developed by Menger and Portnoy as well as Berezin's phase separation model. The binding and partition constants and the transfer free energy from water to micelle have been estimated and discussed, suggesting that the solubilization of both the reactants in the micellar phase, facilitates the oxidation. © 1993 John Wiley & Sons, Inc.     

The use of selenium(IV) chloride for the preparation of diarylselenium dichlorides

Two new synthetic routes for the preparation of diarylselenium dichlorides are reported both of which use selenium(IV) chloride as a starting meterial. In the first method, bis(p-methóxyphenyl) and bis(p-ethoxyphenyl)-selenium dichlorides are prepared by the reaction of SeCl₄ with anisole and phenetole respectively. In the second, diphenylselenium dichloride is prepared by the reaction of SeCl₄ with tetraphenyllead, a reaction in which the lead—carbon bond is cleaved.The far infrared and Raman spectra of the diarylselenium dichlorides are reported.     

Oxidation of ketones by cerium(IV) in presence of iridium(III) chloride

Kinetic data, in iridium(III) chloride catalyzed oxidation of ethyl methyl ketone (EMK) and methyl propyl ketone (MPK) by cerium(IV) perchlorate in aqueous perchloric acid medium, suggest the formation of complex C₁ between cerium(IV) and organic substrate in the first equilibrium step, which in turn gives rise to another complex C₂ with the catalyst. This second complex in the rate-determining step gives rise to the intermediate products. Interestingly IrCl_3, which is considered to be a sluggish catalyst in alkaline media, was found to surpass the catalytic efficiency of even osmium and ruthenium in acidic media. Rate decreases in the beginning at low acid concentrations, but after reaching to a minimum it becomes directly proportional to acid concentrations. Probably on increasing the acid concentrations hydrolyzed species of ceric perchlorate gradually converts into the un-hydrolyzed species, which then accelerates the rate at higher [H⁺], resulting in the observed peculiar effect of hydrogen ions on the rate. Initial concentrations of cerium(IV) and acid determine the extent of reduction of cerium(IV) by water. Order of the reaction shows direct proportionality with respect to the oxidant and ketones at their low concentrations, but tends to become zeroth order at their higher concentrations. Rate of the reaction shows direct proportionality with respect to [IrCl₃] while change in ionic strength of the medium does not affect the reaction velocity. Parameters such as the energy of activation, free energy of activation and entropy data suggest that methyl propyl ketone forms the activated complex more easily compared to ethyl methyl ketone.