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Polyalcohol liquefaction can be performed by acid or base catalysis, producing polyols with different properties. This study compared the mechanical properties of foams produced using polyols from liquefied Cytisus scoparius obtained by acid and base catalysis and using two different foam catalysts. The differences were monitored using FTIR analysis. Acid-catalyzed liquefaction yielded 95.1%, with the resultant polyol having an OH index of 1081 mg KOH/g, while base catalysis yielded 82.5%, with a similar OH index of 1070 mg KOH/g. Generally, compressive strength with dibutyltin dilaurate (DBTDL) ranged from 16 to 31 kPa (acid-liquefied polyol) and 12 to 21 kPa (base-liquefied polyol), while with stannous octoate (TIN), it ranged from 17 to 42 kPa (acid) and 29 to 68 kPa (base). Increasing water content generally decreased the compressive modulus and strength of the foams. Higher water content led to a higher absorption at 1670 cm−1 in the FTIR spectrum due to the formation of urea. Higher isocyanate indices generally improved compressive strength, but high amounts led to unreacted isocyanate that could be seen by a higher absorption at 2265 cm−1 and 3290 cm−1. DBTL was shown to be the best foam catalyst due to higher trimer conversion seen in the spectra by a higher absorption at 1410 cm−1. Acid- and base-derived polyols lead to different polyurethane foams with different FTIR spectra, particularly with a higher absorption at 1670 cm−1 for foams from acid-derived liquefaction. [ABSTRACT FROM AUTHOR]

Pollution of the marine environment with organotin compounds is a serious environmental problem due to their extreme toxicity to a wide range of organisms. A high level of contamination with butytin compounds was detected in the bottom sediments of the Koporye Bay, the Gulf of Finland, the Baltic Sea. The concentration of tributyltin and dibutyltin reached up to 35.7 ng(Sn)/g DW and 9.7 ng(Sn)/g DW, respectively. The butyltin compounds transformed in bottom sediments due to the activity of autochthonous sediment microbiota. The degradation rate of tributyltin and dibutyltin was 0.014 day-1 and 0.022 day-1, their half-life, 49.5 and 31.5 days, respectively. Metagenomic analysis revealed the changes in taxonomic composition and the decrease in species diversity of the bottom sediment microbiomes during the transformation of organotin compounds. During the biodegradation of butyltin compounds in bottom sediments, the abundance of bacteria of the genera Acidithiobacillus, Halothiobacillus, Alicyclobacillus, Sulfurospirillum, Denitrovibrio, as well as of methanogenic archaea of the genus Methanolobus increases, which may indicate their potential participation in the biodegradation of organotin compounds. These results may be used to identify active tributyltin degraders for developing self-purification methods of bottom sediments contaminated with organotin compounds.

The interaction of dibutyltin(IV) dichloride (DBT) with 1,4-diazacycloheptane (homopiperazine, HP) was investigated. In solutions, the complexes formed a 1:1 complex, its protonated and hydrolyzed forms. The formation constants of the complexes and thermodynamic parameters as ΔH° and ΔS° were estimated. The optimization of the structure of the (Bu)2Sn(HP)Cl2 complex reveals that the tin is six-coordinate in a distorted octahedral geometry, where the two nitrogen atoms of homopiperazine and the two chloride ions are in one plane. The solid (Bu)2Sn(HP)Cl2 complex with homopiperazine was synthesized, and the composition was assigned by elemental micro-analysis and mass spectrum. The complex was investigated by infrared, mass spectra, and thermal measurements. The ligand and its complex were tested against antimicrobial Staphylococcus aureus (+ve), Escherichia coli (−ve), and antifungal Candida albicans and Aspergillus flavus. Anticancer activities of homopiperazine and its dibutyltin(IV) complex were tested against breast cancer cell lines. The molecular docking investigations were performed to know the possible modes of binding to the most active sites of the breast cancer oxidoreductase receptor and those of Escherichia coli. [ABSTRACT FROM AUTHOR]

In this work, three organotin (IV) derivatives namely dibutyltin(IV) di-2-hydroxybenzoate (DBT2-HBz) (2), dibutyltin(IV) di-3-hydroxybenzoate (DBT3-HBz) (3) and dibutyltin(IV) di-4-hydroxybenzoate (DBT4-HBz)) (4) were synthesized and tested as disinfectant against pathogenic bacteria, Staphylococcus aureus. Compounds 2–4 were prepared by reacting dibutyltin(IV) oxide (DBTO) (1) with 2-hydroxybenzoic acid (2-HHBz), 3-hydroxybenzoic acid (3-HHBz) and 4-hydroxybenzoic acid (4-HHBz). The synthesized compounds were characterized by spectroscopic techniques including UV–Vis, FT-IR, 1H NMR, and 13C NMR, and micro-elemental analyzer. The optical density (OD) of compounds was measured by UV–Vis at 600 nm, which showed good bioactivity against the S. aureus. The data obtained indicated that compound 4 has higher bioactivity than compound 2 and 3, and the positive control using a commercial disinfectant containing 5 % benzalkonium chloride. The optimum bioactivity of compound 4 was observed at a concentration of 5 × 10−4 M with a contact time of 10 min, as shown by the decrease in absorbance from 0.6092 to 0.4005. Compound 2 was optimal at a concentration of 5 × 10−4 M with a contact time of 10 min, and the absorbance decreased from 0.6092 to 0.4416. Compound 3 and positive control showed a smaller decrease in absorbance compared to compound 4 and 2. Overall, the results obtained indicated that the compounds synthesized have promising potential as disinfectant against pathogenic bacteria. [ABSTRACT FROM AUTHOR]

The structure of the 2-((E)-((Z)-3-(((4-hydroxyphenyl)amino)methylene)-4-oxocyclohexa-1,5-dien-1-yl)diazenyl)benzoic acid (H3L) was confirmed by single crystal X-ray diffraction and Hirshfeld surface analysis was used further to quantify the intermolecular interactions. It crystallized in monoclinic space group P21/c. The observed bond distances evidence that the structure exists predominately in azo-enamine tautomeric form in the solid state. A novel dibutyltin(IV) complex, [(Bu2SnHL)2] (1) was synthesized from H3L. The complex was then characterized by studying different techniques including elemental analysis, FT-IR, and NMR (1H, 13C, and 119Sn) spectroscopy. In solution state, the molar mass of the compound was confirmed by Mass spectrometry. Spectroscopy study guides to predict the structure of the complex which is supposed to be a cyclic dimer [(Bu2SnHL)2] and Sn(IV) adopts a six-coordinated geometry. However, in solution Sn(IV) adopts four coordinated distorted tetrahedral geometry which was supported by 119Sn NMR spectroscopy (δSn(119), 126.34 ppm) and EI-MS results of the complex ion ([C28H32N3O4Sn]+,m/z 593.1). Further, the structures in solid and solution state were supported by developing their optimized structures and IR data from the DFT calculation. The crystal structure of the ligand is in azo-enamine tautomeric form and in accordance with DFT study, its dibutyltin(IV) complex is a cyclic dimer, (Bu2SnHL)2, which becomes monomer in solution. [ABSTRACT FROM AUTHOR]

Liquid crystalline elastomer networks cross‐linked by dynamic covalent bonds (xLCEs) possess the remarkable capability of being (re)processed during plastic flow at high temperatures, while also allowing for the (re)programming of their local alignment. However, the current generation of xLCEs cannot be extruded directly into filaments or injection‐molded into shapes capable of actuation. Here, a novel poly(thio‐urethane) (PTU) LCE thermoset is presented. The inclusion of dibutyltin dilaurate as a catalyst enables the manipulation of the elastic–plastic transition through two distinct pathways. The dissociative equilibrium exchange between the thio‐urethane linkage to form separate thiol and isocyanate competes with the associative exchange of thio‐urethane and a free isocyanate or thiol groups. The temperature of fast plastic flow onset is ≈160 ˚C, and the associated bond‐exchange activation energy is ≈54 kJ mol−1. The hydrogen bonding below the elastic‐plastic transition makes the elastomer robust and extremely ductile with a failure strain exceeding 600% and a Shore hardness A of 72, preventing any creep during cyclic thermal actuation. The versatility of this dynamically cross‐linked elastomer is successfully demonstrated by extruding it using a commercial twin‐screw extruder, injection molding it into required shapes, and hot‐pressing it into flat films or shapes. [ABSTRACT FROM AUTHOR]

Two organotin aryloxyacetate were synthesized by the reaction of 1,2-phenylenedioxydiacetic acid with dibutyltin oxide and tricyclohexyltin hydroxide. The structures were characterized by IR, 1H, 13C NMR, and X-ray crystal diffraction. Herbicidal activity of the prepared organotin aryloxyacetate was evaluated. [ABSTRACT FROM AUTHOR]

The reaction of 1-(4,5-dimethoxy-2,3-dinitrophenyl)-2-methylpropan-1-ol and butylisocyanate using dibutyltin dilaurate as a catalyst afforded 1-(4,5-dimethoxy-2,3-dinitrophenyl)-2-methylpropyl N-butylcarbamate, C17H25N3O8, which released butylamine upon photoirradiation. Single crystals of the title compound were grown in a 1:1 mixed solution of hexane and ethyl acetate. Two nitro groups and one methoxy group are twisted out of the plane of the aromatic ring in the novel photo-protecting group. Intermolecular hydrogen bonds are observed between N-butylcarbamate moieties parallel to the a axis. [ABSTRACT FROM AUTHOR]

Dibutyltin(IV) maleate (DBTML) was successfully used as a new initiator in the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) under solvent-free condition for the first time. The performance of DBTML in the ROP of ε-CL was powerfully and rapidly determined by the non-isothermal differential scanning calorimetry technique. The effect of DBTML concentration on the non-isothermal ROP of ε-CL was studied and described. The values of activation energy (Ea) were completely determined by the peak method of Kissinger and the isoconversional method of Kissinger–Akahira–Sunose (KAS). The Ea values for the ROP of ε-CL decreased with increasing DBTML concentration. The frequency factor (A) values for the ROP of ε-CL with 3.0 and 4.0 mol% of DBTML were 7.4 × 106 and 7.3 × 105 min−1, respectively. From mechanistic investigation by proton-nuclear magnetic resonance spectroscopy (1H-NMR), the ROP of ε-CL with DBTML was purposed via the coordination-insertion mechanism. From bulk polymerization, DBTML could produce poly(ε-caprolactone) (PCL) with the weight average molecular weight (Mw) and polydispersity index (PDI) in the range of 1.49 × 104–5.15 × 104 g/mol and 1.52–1.98, respectively. [ABSTRACT FROM AUTHOR]

Mechanistic implications of antimicrobial and in vitro antioxidant potentials of a set of newly generated nonbridged mononuclear N,O‐orthometallated and carboxylate bridged binuclear nonorthometallated dibutyltin(IV) formulations have been investigated. Some of these formulations were screened for their antibacterial and antifungal activities against Escherichia coli and Candida albicans, respectively whereas in vitro antioxidant potential was examined by Ferric reducing antioxidant power (FRAP) assay. Nonbridged mononuclear N,O‐orthometallated dibutyltin(IV) formulations were generated by the reactions of Bu2SnCl2 with sodium salts of 2‐aminophenol/substituted 2‐aminophenol and flexible N‐protected amino acids in 1:1:1 molar ratio in refluxing dry THF. Plausible structures of these nonbridged mononuclear N,O‐orthometallated dibutyltin(IV) formulations containing flexible N‐protected amino acids have been suggested on the basis of spectroscopic and mass studies of some representative formulations. Plausible structures suggested on the basis of spectroscopic studies are corroborated by density functional theory (DFT/B3LYP method) (SPARTAN‐20) investigation of a representative dibutyltin(IV) complex and the ligands involved in it. The presence of two different classes of organic ligands in this complex provides an opportunity to study optimized topologies, bonding, distortions, optimized energy, and stability of the complex. [ABSTRACT FROM AUTHOR]

Environmental contaminant exposures occur due to the widespread use of synthetic chemicals. Tributyltin (TBT), dibutyltin (DBT), and pentachlorophenol (PCP) are each used in a variety of applications, including antifouling paints and stabilizers in certain plastics. Each of these compounds has been found in human blood, as well as other tissues, and they have been shown to stimulate pro-inflammatory cytokine production in human immune cells, Inflammatory cytokines mediate response to injury or infection. However, if their levels are increased in the absence of an appropriate stimulus, chronic inflammation can occur. Chronic inflammation is associated with a number of pathologies including cancer. Stimulation of pro-inflammatory cytokine production by these toxicants is dependent on activation of ERK 1/2 and/or p38 MAPK pathways. MAPK pathways have the capacity to regulate translation by increasing phosphorylation of key translation regulatory proteins. There have been no previous studies examining the effects of TBT, DBT, or PCP on translation. The current study shows that ribosomal protein S6 (S6), eukaryotic initiation factor 4B (eIF4B), and eIF4E are phosphorylated (activated) and/or their total levels are elevated in response to each of these compounds at concentrations found in human blood. Activation/increased levels of translational proteins occurred at concentrations of the compounds that have been shown to elevate pro-inflammatory cytokine production, but where there is no increase in mRNA for those proteins was seen. Compound-stimulated increases in translation appear to be part of the mechanism by which they elevate protein production in immune cells. [ABSTRACT FROM AUTHOR]

Organotin compounds are organometallic compounds composed of one or more tin-carbon (Sn-C) bonds. Organotin compounds have been shown to have anticancer, antibacterial, and antitumor activities. Based on the several activities of the organotin group, it is hoped that the Dibutyltin (IV) Bis-N-Benzylmethyl Dithiocarbamate compound has the potential to be developed as a new drug candidate. To be a candidate for a new drug, the study was aimed to test and determine the safety level of the compound. Study to determine the LD50 value and category of toxicity of the Dibutyltin (IV) Bis-N-Benzylmethyl Dithiocarbamate compound in white mice (Mus musculus). This research is a laboratory experimental study using 40 white mice, consisting of 20 male mice and 20 female mice. The dose of the test substance was 240, 480, and 960mg/Kg body weight. Observations of mice were carried out for 24 hours by observing the number of dead animals and seeing toxic symptoms, body weight, and ROW (Relative Organ Weight) then the data were analyzed statistically. The results showed that the dose of 960 mg caused the most death with LD50 values of 776.2mg and 794 .3mg of toxic symptoms, weight loss in mice, and an effect on ROW. This compound can cause death in male and female mice, with the LD50 value of male mice being 776.2mg/kg body weight and female mice at 794.3mg/ kg body weight, and this compound is categorized as slightly toxic. [ABSTRACT FROM AUTHOR]

Dinuclear dibutyltin complexes {[2-O-C6H4(O)C=N-N=C(O)CPh2O](n-Bu2Sn)2}n (C1) and {[2-(3-O-C8H6)(O)C=N-N=C-2-(3-O-C8H6)]2(n-Bu2Sn)2}n (C2) have been synthesized and characterized by IR, 1H, 13C, and 119Sn NMR spectra, HRMS, elemental analysis, and thermal stability analysis. Their crystal structures have been determined by X-ray diffraction. In vitro antitumor activities of both complexes have been evaluated by the CCK8 method against three human cancer cell lines (MCF-7, NCI-H460, and HepG2), and the complexes have exhibited high activity against MCF-7 and HepG2. [ABSTRACT FROM AUTHOR]

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A new traiazole derivative (4-amino-5-(((5-methyl-1H-benzo[d]imidazol-2-yl)thio)methyl)-2,4-dihydro-3H-1,2,4-triazole-3-thiol, (L), was employed as a chelating ligand to form a dibutyltin chloride complex and improve the poly(vinyl chloride) (PVC) properties. The doped PVC films were characterized via FT-IR, UV-Vis spectrum, elemental analyses (C, H, N, and M (metallic)), and magnetic susceptibility and conductivity measurements. These characterizations were conducted at room temperature, and it was disclosed that the chelating ligand rules as a bidentate chelate. The photostabilization examination of plain and L-doped PVC films was conducted in the presence of ambient air using the accelerating weather tester, where the doping ratio was fixed to 0.5 wt.%. The photostabilization performance of the additive was evaluated by tracking the indexes of carbonyl (ICO), polyene (IPO), and hydroxyl (IOH), and weight loss relationship with irradiation time. It was noticed that the values of ICO, Ipo, and IOH increased as the irradiation time increased, where this improvement relied on the presence of the Bu2SnL complex. [ABSTRACT FROM AUTHOR]

[Display omitted] • Glycomimetic inhibitors of Gal-8 & Gal-9 were prepared in high yields in 1–2 steps. • Impact of C3 aryl substitution on affinity & selectivity to galectins was assessed. • More than 40-fold increase in affinity to Gal-9 over thiodigalactoside was reached. • Glycomimetics were shown to scavenge tandem-repeat galectins from the cell surface. The binding of human galectins by glycomimetic inhibitors is a promising therapeutic approach. The structurally distinct group of tandem-repeat galectins has scarcely been studied so far, and there is hardly any knowledge on their ligand specificity or their inhibitory potential, particularly concerning non-natural carbohydrates. Here, we present the synthesis of a library of seven 3- O -disubstituted thiodigalactoside-derived glycomimetics and their affinity to two tandem-repeat galectins, Gal-8 and Gal-9. The straightforward synthesis of these glycomimetics involved dibutyltin oxide-catalyzed 3,3́- O -disubstitution of commercially available unprotected thiodigalactoside, and conjugation of various aryl substituents by copper-catalyzed Huisgen azide-alkyne cycloaddition (CuAAC). The inhibitory potential of the prepared glycomimetics for Gal-8 and Gal-9 was assessed, and compared with the established galectins Gal-1 and Gal-3. The introduction of C-3 substituents resulted in an over 40-fold increase in affinity compared with unmodified TDG. The structure-affinity relations within the studied series were discussed using molecular modeling. Furthermore, the prepared glycomimetics were shown to scavenge Gal-8 and Gal-9 from the surface of cancer cells. This pioneering study on the synthetic inhibitors especially of Gal-9 identified lead compounds that may be used in further biomedical research. [ABSTRACT FROM AUTHOR]

Herein successfully synthesized new organotin (IV) complex Bu2SnOL by reacting sulfamethoxazole drug as a ligand with dibutyltin (IV) oxide. The synthesized complex was fully characterized by Fourier transform infrared, 1proton nuclear magnetic resonance, 13carbon nuclear magnetic resonance, 119tin nuclear magnetic resonance and ultraviolet-visible spectroscopies. Field emission scanning electronic microscopy was also applied to study the surface morphology of synthesized complex. The above techniques have demonstrated that the complex was prepared with high percentage of purity. This type of compound has various applications in medicine and industry. For example, using it as photo– stabilizer of different plastic polymers (polyvinyl chloride, polystyrene and polyvinyl alcohol). [ABSTRACT FROM AUTHOR]

Previously, dibutyltin dichloride (DBTC) was the putative toxophore for dibutyltin bis‐alkyl and bis‐thio esters. Recent chemical and toxicological data on dioctyltin bis(2‐ethylhexyl thioglycolate) suggest the thioglycolate esters of alkyltins do not generate the dichloride toxophore. Our results, using 119Sn‐nuclear magnetic resonance (NMR) spectroscopy, demonstrated that dibutyltin bis(2‐ethylhexyl thioglycolate) (DBTE) is hydrolyzed to dibutyltin chloro‐(2‐ethylhexyl thioglycolate) (DBTEC) under simulated gastric conditions. No DBTC was detected. DBTE was administered orally to presumed‐pregnant Sprague–Dawley rats in a corn oil vehicle at 2.5, 8.5, and 25.0 mg/kg/day (Gestation Day 5 [GD5] through GD19). There were no maternal deaths, no treatment‐related statistically significant reductions in feed consumption, maternal body weight or weight gain, or adverse gestational outcomes. Maternal thymus weight was significantly reduced in rats at 25 mg/kg. There were no effects on fetal growth, no dose‐dependent pattern of external, visceral, or skeletal malformations, and no increase in anatomical variations. Based on the obtained experimental data, it is concluded here that DBTE forms DBTEC, not DBTC, in the stomach, and DBTE was not teratogenic nor fetotoxic in rats, a species sensitive to DBTC. The maternal no‐observed‐adverse‐effect level (NOAEL) was 8.5 mg/kg/day, and the developmental NOAEL was 25 mg/kg/day, the high dose. The maternal LOAEL was 25 mg/kg/day based on reduced maternal thymus weight. Dibutyltin bis(2‐ethylhexyl thioglycolate) (DBTE) forms dibutyltin chloro‐(2‐ethylhexyl thioglycolate) (DBTEC) in gastric milieu, not dibutyltin dichloride (DBTC). Daily oral DBTE doses (2.5, 8.5, and 25.0 mg/kg/day [GD5–GD19]) reduced maternal thymus weight 25 mg/kg but produced no adverse gestational outcomes. We conclude DBTE metabolizes to DBTEC, not DBTC, in the stomach, and DBTE was not developmentally toxic in rats. Read‐across of DBTC developmental effects to DBTE is not justified. The maternal and developmental NOAEL for DBTE were 8.5 and 25 mg/kg/day, respectively. [ABSTRACT FROM AUTHOR]

A tin-bromine-containing resin was prepared by the interaction of industrial ED-16 epoxy resin with dibutyltin dibromide. A comparative study of the physical, mechanical and relaxation properties of composites based on the original and modified resins cured at different temperatures has been carried out. It has been shown that the composite materials based on a modified resin are characterized by lower values of tensile strength, elastic modulus, fracture work and glass transition temperature as compared with the samples based on the original epoxy resin. The effect of water on the deformation and strength properties of composites was studied. A complex mechanism of the influence of moisture sorbed by the polymer on the complex of properties has been established, which may result from the imposition of the effects of plasticization and additional curing of the epoxy matrix. At short exposure times, the effect of the sorbed liquid is mainly aimed at weakening the intermolecular interaction in the sample, as a result of which its tensile strength decreases and its deformation capacity increases. At long exposure times, postcuring processes prevail, leading to an increase in the crosslinking density and, as a consequence, to a decrease in deformation capacity and an increase in the strength index. It has been shown that epoxy composites containing resin modified with dibutyltin dibromide are characterized by increased fungitoxicity and fire resistance. The studied polymers can be considered as promising for the production of antifouling coatings for hydraulic equipment on their basis. [ABSTRACT FROM AUTHOR]

The synthesis and comparative study on the antibacterial activity of three organotin(IV) compounds, namely dibutyltin(IV) bis-(3-hydroxybenzoate), [Bu2Sn(3-HBz)2] (7), diphenyltin(IV) bis-(3-hydroxybenzoate), [Ph2Sn(3-HBz)2] (8), and triphenyltin(IV) 3-hydroxybenzoate, [Ph3Sn(3-HBz)] (9) which were prepared by the reaction of dibutyltin(IV) oxide, [Bu2SnO] (4), diphenyltin(IV) dihydroxide, [Ph2Sn(OH)2] (5), and triphenyltin(IV) hydroxide, [Ph3SnOH] (6) with 3-hydroxybenzoic acid (3-HBz) has successfully been performed. The characterization of these compounds were done using 1H and 13C NMR, IR, UV spectroscopies and their compositions were determined based on microanalytical data. Antibacterial activity of these compounds was demonstrated at concentrations of 1.89 × 10−4, 1.81 × 10−4, and 1.72 × 10−4 M, respectively by dilution method against Pseudomonas aeruginosa. Similarly, the compounds were active at concentration of 1.87 × 10−4, 1.79 × 10−4, and 1.71 × 10−4 M, respectively, against Bacillus subtilis. These activities are comparable to that of streptomycin at a concentration of 1.70 × 10−4 M as a positive control, but the halozone of compounds 7, 8, and 9 were slightly lower than that of streptomycin's halozone. The results obtained suggest that the compounds synthesized have potential as antibacterial agents. [ABSTRACT FROM AUTHOR]

Over the past several decades significant biological activities including brains protective and antimicrobial activities have made sugar esters (SEs) as a topic of great interest. In this context, unimolar 3-chlorobenzoylation of methyl α-L-rhamnopyranoside (4) using dibutyltin oxide method regioselectively furnished only the 3-O-substitution product 5 in excellent yield. The reaction proceeded via the formation of a cyclic 2,3-Odibutylstannylene intermediate where equatorial hydroxyl group is activated by the tin atom leading to the formation of product 5 only. To get biologically important rhamnopyranoside esters chlorobenzoate 5 was further converted into three newer 2,4-di-O-acyl products 6-9 with other acylating agents using direct acylation method. Prediction of activity spectra for substances (PASS) indicated that these rhamnopyranoside esters have many promising biological profiles including CYP2H substrate, membrane permeability inhibitor and better antifungal activities. Additionally, ADMET and drug likeness properties of SEs 5-8 were predicted and discussed. [ABSTRACT FROM AUTHOR]

Complex 1 was synthesized by the reaction of 4-(4-hydroxynaphthylazo)-benzoic acid with trimethyltin(IV) chloride in anhydrous methanol using triethylamine as base while 2 was synthesized by the reaction of 3-(2-hydroxynaphthylazo)-benzoic acid with dibutyltin(IV) oxide in anhydrous toluene. The complexes were characterized by elemental analysis, IR, and multinuclear (1H, 13C, and 119Sn) NMR spectroscopy. The coordination behavior and geometries around tin in 1 and 2 were established by X-ray crystallography while geometries of the complexes in solution were determined by 119Sn-NMR spectroscopy. The polymeric 1 displayed slightly distorted trigonal bipyramidal geometry around the tin with the equatorial plane occupied by three methyl groups and the axial positions occupied by a carboxylate oxygen and a phenoxide oxygen of another ligand. The tetranuclear 2 exhibited a bis[dicarboxylatotetraorganodistannoxane] type structure with a non-centrosymmetric Sn2O4 core where the central Sn2O2 ring was connected to two exo-cyclic tin ions through μ3-oxo atoms. The coordination geometry around exo- and endo-cyclic tin ions was distorted octahedral and deformed square pyramidal, respectively. 119Sn NMR spectral study suggested four-coordinate tetrahedral 1 while six- and five-coordinate structures around exo- and endo-cyclic tin ions for 2 in solution. [ABSTRACT FROM AUTHOR]

A series of novel dibutyltin complexes based on salen-like ligands (S01 – S03) were synthesized and characterized using ultraviolet-visible spectra，infrared spectra, 1H, 13C, and 119Sn nuclear magnetic resonance, high-resolution mass spectrometry, X-ray crystallography, and thermogravimetric analysis. Complex S03 had excellent anticancer activity in vitro (IC 50 = 1.5 ± 0.2 μM in CAL-27 cell lines), which highly activated ROS expression levels and induced apoptosis and cell cycle arrest at the G2/M phase. Interestingly, complex S03 induced cancer cell death through multiple mechanisms (mitochondrial pathway, ER-stress pathway, and DNA damage pathway). This study reveals new mechanisms of organotin complexes and provides new insights into the development of organotin metal complexes as anticancer drugs in the future, and compounds with multiple anticancer mechanisms may be a new strategy for delaying or overcoming drug resistance to chemotherapy and target therapy. The novel dibutyltin complex S03 has excellent anticancer activity and multiple mechanisms to kill cancer cells. [Display omitted] • A series of novel dibutyltin complexes (S01–S03) were synthesized and characterized. • Complex S03 has excellent antitumor activity and multiple mechanisms to kill cancer cells. • Complex S03 may be developed as a new chemotherapeutic drug. [ABSTRACT FROM AUTHOR]

Abstract Background Mozambique tilapia (Tilapia mossambica) are commonly used in the assessment of aquatic environment quality and also considered as useful bio-indicators during environmental pollution monitoring. Copper-oxide and dibutyltin are used as antifouling underwater hall paints. Copper nanoparticles (Cu-NPs) are serious water pollutants but their impact in fish’s performance remains poorly understood. Results In the present study, we have exposed tilapia, a freshwater edible fish to two different doses (15 mg/L) of Cu-NPs and (2 mg/L) dibutyltin for 6 days. The doses selected were eco-relevant considering the contamination levels of certain water resources. The results indicated that the activity oxidative stress enzymes reduced glutathione (GSH), acetylcholinesterase (AChE), and glutathione-S-transferase (GST) were significantly decreased in the liver, brain, and gills of the treated groups when compared to control. Conclusion Taken together, the results suggest that short-term exposure of tilapia fish to Cu-NPs and dibutyltin causes oxidative stress and impart serious deleterious effects in the tissues which may affect fish growth and development and causes death. In the case of the gills, liver, and brain when exposed to both concentrations of CuO and dibutyltin (NPs), although the activity of these enzymes showed an inhibition in the liver when exposed to both concentrations of NPs. The present study investigated that CuO-NPs are more toxic than dibutyltin.

Copyright of Japanese Journal of Food Chemistry & Safety is the property of Japanese Society of Food Chemistry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Display omitted] The combination of a dibutyltin(IV) oxide catalyst with an ortho ester as the dehydrating agent exhibited high activity for the direct synthesis of diethyl carbonate from CO 2 and ethanol in 78% yield. With water as a by-product limiting the reaction, a recoverable dehydrating agent is required. When alkoxysilanes were employed for this purpose, various dialkyl carbonates were obtained in yields of 33–45%. [ABSTRACT FROM AUTHOR]

Dibutyltin (DBT) is used to stabilize plastics and as a deworming agent in some poultry. It is found in human blood (levels as high as 0.3 μM). Interleukin (IL) 1β (IL‐1β) and IL‐6 are pro‐inflammatory cytokines produced by lymphocytes, monocytes, and other cells. Elevated levels of IL‐1β and IL‐6 have been associated with pathologies including rheumatoid arthritis and cancers. DBT was shown to decrease IL‐1β and IL‐6 secretion from immune cells at higher concentrations while causing increases at lower concentrations. However, it was not clear if these changes were due to DBT's alteration of the secretory process or due its ability to change cellular synthesis/production of these proteins. This study addresses this question, as well as mechanisms for any observed changes in synthesis/production. Monocyte‐depleted peripheral blood mononuclear cells (MD‐PBMCs) were exposed to DBT at concentrations of 5, 2.5, 1, 0.5, 0.25, 0.1, and 0.05 μM for 1, 6, and 24 h and the production (combination of secreted and intracellular levels from the same cells) of both IL‐1β and IL‐6 were measured. Effects of selected DBT exposures on cytokine production were also examined in PBMCs and DBT's effects were similar when monocytes were present. The 24‐h exposures to DBT decreased production of both IL‐1β and IL‐6 at the two highest concentrations but increased production at lower concentrations. Both decreases and increases in cytokine production appear to be explained by DBT‐induced changes in mRNA levels. DBT‐induced increases in cellular production of the cytokines appear to require p38 and ERK1/2 MAPK pathways. Dibutyltin(DBT),an environmental contaminant found in human blood, alters the synthesis/production of the inflammatory cytokines IL‐1β and IL‐6 from immune cells. 24 h exposures to DBT decreased synthesis/production of both IL‐1β and IL‐6 at the two highest concentrations but increased synthesis/production at lower concentrations. Both decreases and increases in cytokine production appear to be explained by DBT induced changes in mRNA levels. DBT‐induced increases in cellular production of the cytokines appear to require p38 andERK1/2 MAPK pathways. [ABSTRACT FROM AUTHOR]

Dibutyltin(IV) complexes 1–3 were synthesized by the reaction of either dibutyltin(IV) oxide or dibutyltin(IV) dichloride with azo-carboxylic acid ligands viz. 2/4-(2-hydroxynaphthylazo)-benzoic acids in different stoichiometric reaction ratios. The complexes were characterized by elemental analysis and UV, IR and multinuclear [1H, 13C and 119Sn]-NMR spectroscopy. The geometry and mode of coordination around tin atoms in the complexes in the solid state were determined by X-ray crystal structure analysis. Complex 1 exhibited a dinuclear structure with a distorted square-pyramidal geometry around each Sn atom. Compound 2 showed a bis[dicarboxylatotetraorganodistannoxane] type structure {[R2Sn(O2CR′)]2O}2 that contained a centrosymmetric Sn2O4 core in which the Sn2O2 ring was connected to the exo-cyclic tin atom through μ3-oxo O-atoms. The coordination geometry around exo- and endo-cyclic tin atoms was intermediate between square-pyramidal and trigonal bipyramidal and distorted octahedral, respectively. In 3, the coordination sphere around the tin atom adopted a skew-trapezoidal bipyramidal geometry. The 119Sn NMR study suggested a 5-coordinate structure in complexes 1 and 3 in the solution state, while in 2 the geometry around exo- and endo-cyclic tin atoms was found to be a five and six coordinate structure, respectively. Thus, the solid state structure of 1 and 2 is retained in solution, while in 3 the solid state structure is dissociated. The anti-diabetic activity of the complexes was also studied and the results of the assays showed significant activity of compound 2 compared to 1 and 3. [ABSTRACT FROM AUTHOR]

Macrophages and myofibroblasts are important in fibrogenesis. The cellular characteristics in pancreatic fibrosis remain to be investigated. Pancreatic fibrosis was induced in F344 rats by a single intravenous injection of dibutyltin dichloride. Histopathologically, the induced pancreatic fibrosis was divided into 3 grades (1+, 2+, and 3+), based on collagen deposition. Immunohistochemically, CD68-expressing M1 macrophages increased with grade and CD163-expressing M2 macrophages also increased later than M1 macrophage appearance. Double immunofluorescence showed that there were macrophages coexpressing CD68 and CD163, suggesting a possible shift from M1 to M2 types; similarly, increased major histocompatibility complex class II- and CD204-expressing macrophages were polarized toward M1 and M2 types, respectively. These findings indicated the participation of M1- and M2-polarized macrophages. Mesenchymal cells staining positive for vimentin, desmin, and α-smooth muscle actin (α-SMA) increased with grade. There were mesenchymal cells coexpressing vimentin/α-SMA, desmin/α-SMA, and glial fibrillary acidic protein (GFAP)/α-SMA; Thy-1-expressing immature mesenchymal cells also increased in fibrotic lesions. Because α-SMA expression is a reliable marker for myofibroblasts, α-SMA-expressing pancreatic myofibroblasts might be originated from GFAP-expressing pancreatic stellate cells or Thy-1-expressing immature mesenchymal cells; the myofibroblasts could simultaneously express cytoskeletal proteins such as vimentin and desmin. The present findings would provide useful information for analyses based on features of macrophages and myofibroblasts in chemically induced pancreatic fibrosis. [ABSTRACT FROM AUTHOR]

A series of rigid polyimide (PI) foams were prepared by the prepolymer method with pyromellitic dianhydride and polyaryl polymethylene isocyanate as the starting materials and dibutyltin dilaurate (DBTDL), and triethanolamine (TEOA) as catalysts. The effect of the two kinds of catalysts on the structure and properties such as molecular structure, cell morphology, density, mechanical properties, thermal properties, and flame retardancy of the resulting foams were characterized in detail. The experimental results showed that the PI foams prepared in this work possessed low density, good mechanical properties, outstanding thermal stability, and excellent flame retardancy. The thermal stability and flame retardancy were improved obviously with the increase of DBTDL content. While with the increase of the content of TEOA, the mechanical strength and apparent density of PI foams increased significantly. Therefore, different structure and performance of PI foams can be prepared by adjusting the content of these two catalysts. J. VINYL ADDIT. TECHNOL., 25:385–395, 2019. © 2019 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Exposure to tin in the general US population is near ubiquitous, as determined using urinary tin levels measured by inductively coupled plasma mass spectrometry (ICP-MS). Urinary tin levels are associated with chronic health outcomes, such as diabetes; however, it is unclear if these associations are due to the presence of inorganic and organic forms of tin in urine. To address this knowledge gap, levels of total tin and several organotin compounds (OTCs) were measured in convenience urine samples from pregnant women and adults from Iowa, United States. Total tin and OTC levels in urine samples were quantified using ICP-MS and gas chromatography with pulsed flame photometric detection (GC-PFPD), respectively. ICP-MS detected tin in almost all urine samples from both study populations. Low levels of dibutyltin were detected in two out of fifty human urine samples. Importantly, storage of urine samples in plastic containers, but not HNO3-pretreated glass vials drastically reduced the recoveries of OTCs, in particular, tributyltin. Although their detection frequency is low, exposures to OTC should be considered when studying associations between human exposures to tin compounds and adverse health outcomes; however, urinary OTC levels measured in banked urine samples may not be suitable as biomarkers of OTC exposure. [ABSTRACT FROM AUTHOR]

Abstract FTIR spectra of neat dibutyl ether (DBE), methanol (MeOH) and their binary solutions at different mole fractions have been recorded at room temperature. The density functional theory (DFT) calculations have been carried out on DBE monomer, MeOH (monomer, dimer, timer, tetramer, pentamer and hexamer) and DBE-MeOH H-bonded networks. These studies reveal that neat MeOH is a mixture of more than one type of multimers while the solution may consists of any of the combination of neat DBE/MeOH multimers which do not participate in heterointeraction, and 1:1, 1:4, 1:5 and 1:6 complexes. The donor-acceptor interaction energies are found to be larger in 1:4 (DBE:MeOH) complex. Time domain reflectometry (TDR) study has also been carried out on the binary solution of DBE with MeOH in the frequency range of 10 MHz–26 GHz at 298 K. The dielectric parameters have been correlated with the findings of FTIR and theoretical studies. Graphical abstract Image 1 Highlights • Unusual intensity changes of O − H stretching band on dilution. • Neat MeOH: Mixture of more than one type of multimers. • Only (M e O H) O − H ⋯ O − C (M e O H) interactions in neat MeOH. • (M e O H) O − H ⋯ O − C (D B E) , (D B E m e t h y l e n e) C − H ⋯ O − C (M e O H) hetrointeractions in solutions. • τ value for neat MeOH, smaller in size than DBE, is larger. [ABSTRACT FROM AUTHOR]

The kinetics of catalyzed by dibutyltin dilaurate reaction of polyurethane foam synthesis infused with 1 wt% of fillers was studied in dependence of Type 1D (nanosized [multi‐wall carbon nanotubes] or macrosized [carbon fibers]) or 2D (thermoexpanded graphite) carbonaceous fillers by IR spectroscopy and optical microscopy. It is shown that the foaming reaction has two stages: the first stage being a first‐order reaction, and the second stage a second‐order reaction. The mean diameter of the bubbles and the bubble size distribution has been determined during the process of foaming. It is shown that the presence of 2D fillers leads to a decrease in the mean diameter of the bubbles. POLYM. ENG. SCI., 59:941–948, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Several areas within the Bahía Blanca estuary (BBE), with different maritime traffic intensity, were studied in order to confirm the presence and assess the distribution of tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) in the water column. The organotin compounds (OTCs) were determined in the water samples—taken in summer, autumn, winter, and spring of 2014—by gas chromatography coupled to mass spectrometry after liquid-liquid extraction with hexane. The incidence of TBT throughout the whole sampling period indicated a continuous presence of this compound to the study area. However, in accordance with the butyltin degradation index (BDI), TBT was not recently introduced in the BBE. Furthermore, the average TBT levels exceeded the international guideline established by the Oslo-Paris commission (0.62 ng Sn L−1). As a result, certain biological effects could be expected to occur in sensitive species such as mussels. While DBT were below the detection limit in the 75% of the samples analyzed, MBT was detected in all the samples and no significant differences were found among the concentrations measured in the different seasons (Kruskal–Wallis test, p > 0.05). In addition, no correlations were found among the OTCs levels and the evaluated physiochemical parameters (Spearman coefficient, p > 0.05). [ABSTRACT FROM AUTHOR]

Abstract Synthesis of azepine-based compounds are of highly interest due to their vast applications in medicinal filed. In this work, is described the synthesis of a azepine-based derivative, 11-methoxy-6,6a-dihydro-5H-dibenzo[b,e]azepine (MDDA) by new route using dibutyltin dilaurate (DBTDL) as catalyst. The structural elucidation of MDDA was done by FT-IR, 1H NMR, and mass spectrometry techniques. Also is presented the experimental and theoretical DFT study of the vibrational, structural and quantum properties of MDDA using B3LYP exchange-correlation functional with 6-311G (2d, p) basis set. The theoretical DFT geometry optimization data was compared with the X-ray data in the associated literature promoting a good comprehension of the structural arrangement. In complementation, mapped molecular electrostatic potential surface (MEPS), HOMO-LUMO orbitals and NBO energy calculations were also performed using the same calculation approach. The calculated UV spectrum is in good agreement with the experimental one, making the bands assignments possible. The comparative IR studies clearly confirmed the intermolecular hydrogen bonds of the proposed dimeric form for MDDA and also showed several characteristic vibrations within the molecular structure. Graphical abstract Image 1 Highlights • Synthesis of 11-methoxy-6,6a-dihydro-5H-dibenzo[b,e]azepine by new synthetic route. • The DFT and TD-DFT calculations, and molecular dynamics have been assessed. • The small hardness value (η) (1.79 eV) reflects high polarizability. • Molecule has definite poles with a non-uniform distribution of electron density. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Better mechanistic understanding of ROPPOC approach. • Synthesis of optically pure cyclic poly(l -lactide)s. • Results in contradiction to Jacobson-Stockmayer theory. Abstract Starting from dibutyltin oxide, four catalysts were synthesized, namely the dibutyltin bisphenoxides of phenol (SnPh), 4-chlorophenol (SnCP), 4-hydroxybenzonitrile (SnCN) and pentafluorophenol (SnOPF). With the first three catalysts polymerizations of l -lactide at 160 °C in bulk yielded large fraction of linear chains having phenylester end groups at short reaction times. At longer times the fraction of cycles considerably increased at the expense of the linear chains, when SnCN was used as catalyst. With SnOPF only cyclic polylactides were obtained at low Lac/Cat ratios (<400) with weight average molecular weights (M w) up to 90 000 Da, whereas for high Lac/Cat ratios mixtures of cyclic and linear chains were found. Polymerizations in solution enabled variation of the molecular weight. Polymerizations of meso -lactide at temperatures down to 60 °C mainly yielded even-numbered linear chains supporting the postulated ROPPOC mechanism. [ABSTRACT FROM AUTHOR]

Abstract Female marine gastropods develop imposex (growth of penis/vas deferens) when exposed to TBT (tributyltin). Ours, is the first report of an imposex survey associated with TBT in sediment along 920 km of South Africa's Atlantic coastline. We sampled and analysed 1389 individuals of 13 caenogastropod species, and sediment samples from 25 sites, presumed impacted and not impacted by TBT pollution. Imposex was detected in six species not previously reported to suffer from this phenomenon, at eight sites, with up to 100% of females affected. Butyltins were found at quantifiable concentrations at four sites, with TBT and DBT (dibutyltin) concentrations in sediments up to 20 000 μg/kg dry mass (dm) and 3740 μg/kg dm, respectively. These findings are of major concern considering that TBT has been banned globally since 2008 by the International Maritime Organisation (IMO) - more extensive research is required in areas affected by TBT and where aquaculture is present. Highlights • First survey of imposex associated with TBT in sediments from the Atlantic coastline of South Africa • 1389 individuals of 13 caenogastropod species and sediment samples from 25 sites were analysed. • Imposex was detected in six species not previously reported to suffer from this phenomenon. • Measurable concentrations of TBT and DBT were found in sediments from four out of the 25 sites [ABSTRACT FROM AUTHOR]

Abstract: Konjac glucomannan, built of β-1,4-linked mannose and glucose, was methylated after treatment with dibutyltin oxide/MeOH in pyridine. Best results were obtained in acetonitrile/DMF in the presence of TBAB and K2CO3. While total DS was only 0.1-0.15 and not significantly enhanced in the tin-promoted reaction, the manno-/gluco- (cis-/trans-diol) and the regioselectivity was completely changed with DSMan/DSGlc increasing from 0.9 to 1.8, a strong preference for secondary over primary OH, and a total order of reactivity being M3 > M2 ≥ G2 > G6 ≥ M6 ≥ G3. The influence of the amount of K2CO3, Bu2SnO, and temperature was studied. By repeated reaction a DS of 0.28 was gained without loss in selectivity. In a solvent-free one-pot stannylation/methylation reaction, a DS up to 0.3 was achieved. Surprisingly, any differences between the two stereoisomeric sugar constituents were leveled under these conditions, and regioselectivity was changed to the order M6 ≈ G6 ≫ M3 ≈ G3 > M2 ≈ G2.Graphical abstract: [ABSTRACT FROM AUTHOR]

The research complements a study (Pinna et al., 2012) carried out to evaluate the effectiveness of mixtures of consolidants and water-repellent products (tetraethylorthosilicate, methylethoxy polysiloxane, Paraloid B72), with biocides (tributyltin oxide, dibutyltin dilaurate, copper nanoparticles) applied in situ to prevent biological growth on stones. The mixtures were tested over time on trial areas of three substrates - marble, sandstone, and plaster – in the archaeological site of Fiesole (Firenze, Italy). The 8-year-long study showed that the recolonization of the three substrates after the conservation treatment related mainly to their bioreceptivity and to the climatic conditions. Although the mixtures of water repellents and consolidants with biocides and copper nanoparticles were effective in reducing the recolonization, they did not play a crucial role in preventing biofilms and lichens growth. This study demonstrated that it was not possible to draw common conclusions regarding the products’ performance on the examined stones. Copper nanoparticles proved to be a suitable alternative to traditional biocides because they did not alter stones colour and contributed to the prevention of recolonization. The study provided information on the succession of fungi and lichens on untreated and treated stones, as well as on the variations of water repellency of treated stones. [ABSTRACT FROM AUTHOR]

The binding of gold(III) from solution in a 2 M HCl with thallium(I) dibutyl dithiocarbamate leads to the formation of ion-polymeric complex ([Au{S2CN(C4H9)2}2][TlCl4])n, which was studied by (13С, 15N) MAS NMR spectroscopy and X-ray diffraction analysis. In the complex comprising the nonequivalent cations [Au{S2CN(C4H9)2}2]+ (A and B) and anions [TlCl4]-, the supramolecular self-assembly is provided by secondary bonds Au···S and S···Cl. The former are involved in the formation of isomeric binuclear cations [А···А] and [В···В] that build the (···[А···А]···[В···В]···)n polymeric chain; the latter selectively combine the thallium(III) anions and the dimeric cations. Thermolysis of the complex is accompanied by gold recovery and release of TlCl. [ABSTRACT FROM AUTHOR]

The binding of gold(III) from solution in a 2 M HCl with thallium(I) dibutyl dithiocarbamate leads to the formation of ion-polymeric complex ([Au{S2CN(C4H9)2}2][TlCl4])n, which was studied by (13С, 15N) MAS NMR spectroscopy and X-ray diffraction analysis. In the complex comprising the nonequivalent cations [Au{S2CN(C4H9)2}2]+ (A and B) and anions [TlCl4]-, the supramolecular self-assembly is provided by secondary bonds Au···S and S···Cl. The former are involved in the formation of isomeric binuclear cations [А···А] and [В···В] that build the (···[А···А]···[В···В]···)n polymeric chain; the latter selectively combine the thallium(III) anions and the dimeric cations. Thermolysis of the complex is accompanied by gold recovery and release of TlCl. [ABSTRACT FROM AUTHOR]

The preparation of a carbon ceramic electrode modified with SnO2 (CCE/SnO2) using tin dibutyl diacetate as precursor was optimized by a 23 factorial design. The factors analyzed were catalyst (HCl), graphite/organic precursor ratio, and inorganic precursor (dibutyltin diacetate). The statistical treatment of the data showed that only the second-order interaction effect, catalyst × inorganic precursor, was significant at 95% confidence level, for the electrochemical response of the system. The obtained material was characterized by scanning electron microscopy (MEV), X-ray diffraction (XRD), RAMAN spectroscopy, XPS spectra, and voltammetric techniques. From the XPS spectra, it was confirmed the formation of the Si-O-Sn bond by the shift in the binding energy values referred to Sn 3d3/2 due to the interaction of Sn with SiOH species. The incorporation of SnO2 provided an increment of the electrode response for levofloxacin, with Ipa = 147.0 μA for the ECC and Ipa = 228.8 μA for ECC/SnO2, indicating that SnO2 when incorporated into the silica network enhances the electron transfer process. Under the optimized working conditions, the peak current increased linearly with the levofloxacin concentration in the range from 6.21×10−5 to 6.97×10−4 mol L−1 with quantification and detection limits of 3.80×10−5 mol L−1 (14.07 mg L−1) and 1.13×10−5 mol L−1 (4.18 mg L−1), respectively. [ABSTRACT FROM AUTHOR]

Diorganotin(IV) complexes (1‐4) of MESNA (sodium 2‐mercaptoethanesulfonate HSCH2CH2SO3Na) and a mixed ligand complex of dibutyltin(IV), 1,10‐phenanthroline and MESNA (5) were synthesized with thermal and microwave assisted methods. All the complexes were characterized thoroughly with the help of analytical and various spectroscopic techniques viz. FTIR, NMR (1H, 13C, and 119Sn NMR) spectroscopy and ESI‐MS spectrometery. Various spectrophotometric studies were carried out to decipher the binding mode of MESNA and its diorganotin complexes 1‐5 with calf thymus DNA (CT DNA) and thus, to calculate the binding constant (Kb). Absorption spectrophotometric study confirmed the interaction is through partial intercalation of all the complexes including MESNA, inside the DNA helix and calculated binding constant (Kb) is in the order of 103 M‐1. A series of emission spectrophotometric experiments support the results obtained through the absorption spectrophotometric studies. Circular dichroic (CD) spectroscopic analysis and viscosity measurement of CT DNA further complemented the fact that the partial intercalation plays a major role in the interaction of the studied complexes with CT DNA. All the studies corroborated that complex 2 bound to CT DNA with maximum affinity followed by complex 5 among all the complexes. Involvement of hydroxyl radicals as an active species in the cleavage activity of pBR322 plasmid DNA is proved by carrying out agarose gel electrophoretic technique. [ABSTRACT FROM AUTHOR]

A new organo-tin complex has been synthesized and used as a single source precursor for the synthesis of SnSe nanosheets by the hot injection method and thin films by the aerosol assisted chemical vapor deposition (AACVD) method. The films were deposited on glass substrates at three different temperatures. The textural quality and preferential growth were found to be significantly altered by changes in the deposition temperature. Oleylamine capped nanosheets and the as-deposited thin films by AACVD were characterized by powder X-ray diffraction (p-XRD) and microscopic techniques. The thin films were also studied by Raman spectroscopy. The stoichiometry is marginally affected by temperature, and all films were slightly selenium deficient. The synthesized material was also evaluated for the photoelectrochemical (PEC) splitting of water. The PEC study revealed the bifunctional nature of the material, which can be applied for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), by switching the applied potential. [ABSTRACT FROM AUTHOR]

ABSTRACT: Meso‐Lactide was polymerized in bulk at 60, 80, and 100 °C by means of three different types of catalysts: dibutyltin sulfides (2,2‐dibutyl‐2‐stanna‐1,3‐dithiolane and 2,2′‐dibutyl‐2‐stanna‐1,3‐dithiane), dibutyltin derivatives of substituted catechols (BuCa, CyCa, and BzCa), and dibutyltin derivatives of 2,2′dihydroxybiphenyl (SnBi) and 2,2′‐dihydroxy‐1,1′‐binaphthyl (SnNa). Only the latter two catalysts were active at 60 °C. The architecture of the resulting polylactides depends very much on the structure of the catalyst and on the temperature. At the lowest temperature (60 °C), SnBi and SnNa mainly yielded even‐numbered linear chains, but SnNa also yielded even‐numbered cycles at 100 °C and short reaction times. In contrast, BuCa, CyCa, and BzCa mainly yielded odd‐numbered cycles, although the same catalysts yielded even‐numbered linear chains when benzylalcohol was added. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 749–759 [ABSTRACT FROM AUTHOR]

Eliglustat, a ceramide glucosyltransferase inhibitor, was synthesized in six steps with 28.4% overall yield. The key features include the use of a diastereoselective aldol reaction to construct two contiguous stereocenters and a selective sulfonylation of a 1,3-diol catalyzed by dibutyltin oxide. [ABSTRACT FROM AUTHOR]

Organotins present a toxicological risk to biota in the aquatic environment. Understanding the behaviour of these compounds in sediment is challenging, with sophisticated analytical techniques required for their measurement. We investigated the use of silica-bound sorbents for diffusive gradients in thin-films (DGT) adsorption gels to pre-concentrate five organotins (monobutlytin (MBT), dibutyltin (DBT), tributyltin (TBT), diphenyltin (DPhT), triphenyltin (TPhT)) found frequently in coastal sediment. C 8 sorbent showed optimum performance in uptake and recovery of organotins for pH and ionic strength ranges typical of coastal waters. Recoveries from adsorption gels deployed in filtered sea water were MBT = 123 ± 20%, DBT = 75 ± 12%, TBT = 81 ± 16%, DPhT = 72 ± 30%, TPhT = 58 ± 10% respectively. Devices were used to investigate DGT fluxes and pore water concentrations of organotins in coastal sediment collected from a contaminated site. DGT fluxes measured in sediment cores for the five organotins ranged between 4.3 × 10 −8 and 1.6 ×10 −5 ng cm 2 s −1 . The depletion of organotin species within pore waters at the interface with DGT devices was measured over a series of deployment times (2, 7, 14, 21 and 28 days) and provided estimates of the concentration of organotins in pore waters at Langstone Harbour, UK, prior to depletion by the DGT device and information on their spatial heterogeneity. The novel in situ DGT device developed can pre-concentrate organotins from pore waters in coastal sediment core samples and allows their detection at low environmental concentrations using conventional gas chromatographic/mass spectrometric instrumentation. Use of the DGT device overcomes many problems associated with the conventional pore water sampling of organotins. Our preliminary data suggests it has potential in the future to be a useful tool in investigating the environmental fate of these pollutants. The use of the C 8 gel will also allow for the simultaneous sequestration of other semi- and non-polar analytes present in the pore water. [ABSTRACT FROM AUTHOR]

Butyltins (BTs), tributyltin (TBT) and dibutyltin (DBT) are organotin compounds that have been used in a variety of industrial applications; as a result, these compounds have been found in human blood. Interleukin (IL)-6 is a proinflammatory mediator that is produced by T lymphocytes and monocytes. It is responsible for immune response regulation as well as tissue repair and cellular growth. Both BTs decrease the ability of human natural killer cells to destroy tumor cells and alter the secretion of proinflammatory cytokines tumor necrosis factor alpha, interferon gamma and IL-1 beta (β) from human lymphocytes ex vivo. Here, we show that BTs alter the secretion of IL-6 from increasingly reconstituted preparations of human immune cells. IL-6 secretion was examined after 24 hour, 48 hour or 6 day exposures to TBT and DBT in highly enriched human natural killer cells, monocyte-depleted peripheral blood mononuclear cells (PBMCs), PBMCs, granulocytes and a preparation combining both PBMCs and granulocytes (PBMCs + granulocytes). The results indicated that both BTs altered IL-6 secretion from all cell preparations. Significant decreases of IL-6 secretion were seen at the highest concentration of TBT (200 n m) and DBT (5-2.5 μ m) while the lower concentrations of DBT (0.05 and 0.1 μ m) caused elevation of IL-6 secretion. The data indicate that BT-induced alterations of IL-6 secretion from immune cells may be a significant consequence of BT exposures that may potentially affect immune competence. [ABSTRACT FROM AUTHOR]